one of the most active local residential developers
founder and shareholder of Mobexpert Group
The new residential project will be developed in the Pantelimon area of the Capital
on a plot of approximately 27,000 square meters
Located next to Pantelimon Park and Lake, VITALITY EST represents an investment of €50 million. On the 46,400 square meters of total buildable area there will be more than 500 modern apartments, along with approximately 400 square meters of commercial space, designed to provide residents with access to all the amenities necessary for a balanced lifestyle.
“I strongly believe in the power of example and the responsibility we have to raise the standards in real estate and deliver high quality that future generations will appreciate
The Pantelimon area deserves a strong and well-integrated project that emphasizes increasing the quality of life for our future residents
and VITALITY EST is a strategic step in the urban reconstruction that we are undertaking with all our projects,” says Dan Sucu
The project is also well connected to public transportation
Near VITALITY EST there are bus and tram stops
as well as Metro access at Pantelimon Station
the location of the complex also helps with the direct exit to the Autostrada Soarelui
VITALITY EAST will be realized in three phases
and the first phase is scheduled to start in the coming weeks
The next two phases are scheduled for delivery in 2027 and 2028
VITALITY EST marks another important step in REDPORT’s expansion plans. The developer is thus consolidating its position in the real estate market with a new quality-first project that contributes to the transformation of the Romanian residential landscape.
We use cookies for keeping our website reliable and secure
providing social media features and to analyse how our website is used
Romania has in recent years become a darling of western think tanks and war planners
back to work policies and poverty wages have fuelled a record economic “recovery,” as the vast majority of workers struggle to provide basic necessities and have been hit with the highest inflation in the EU
united around a PSD (Social Democratic Party)-led Grand Coalition Government
has helped propel the country to the forefront of the war preparations against Russia
2024 is a year with four rounds of elections in Romania
in which the bourgeois parties and media have barred any mention of the pressing issues confronting the working population: the ongoing COVID-19 pandemic
which continues to wreak havoc on the country’s decrepit health infrastructure
and the looming threat of an all-out war against Russia
A situation at the Pantelimon Hospital Intensive Care ICU unit, which first emerged in April, threatens to lift the veil of silence around the catastrophic state of the country’s health infrastructure, fuelled by the ruling class’ “forever COVID” policy now in place internationally
alerted authorities that 20 people had died in the ICU unit in the space of less than 72 hours
The stated suspicion was that doctors had purposely tampered with the dosage of Norepinephrine
a compound used to maintain the blood pressure of severely ill patients
Three separate medical investigations found no wrongdoing on the part of medical staff
PSD Health Minister Rafila condemned the revelations as “endangering trust in medical personnel.” No mention was made in the investigations and subsequent coverage of the dire state of the healthcare system
The dramatic number of deaths was quickly brushed off
despite revelations by former employees and patients’ rights groups that high mortality in the hospital had persisted for a long time and a mobile morgue unit had been parked inside the courtyard for months
a COVID surge observed throughout the world intensified the catastrophic situation in Romania’s hospitals
a few mammoth units throughout the country shoulder the vast majority of serious cases
These hospitals experience a severe shortage of personnel and are rife with nosocomial (hospital-acquired) infections
as repeated rounds of austerity measures are making new hires very difficult
the University Emergency Hospital of Bucharest (SUUB)
as COVID spread unchecked among patients and caregivers
the ICU unit at Pantelimon hospital was holding up to 40 cases from its normal capacity of 25 beds
prosecutors ordered the arrest of Mirela Păiuș and Maria Miron
two young doctors from the hospital’s ICU unit
An intense media campaign was started by the prosecutors
with details from the case either leaked or read directly by the state office
and their full names and images were published in the press
Private conversations with family members in which they grapple both with the seriousness of the cases and with the threat of prosecution were “leaked” and misused in the media
A parallel campaign was started on far-right social media channels
connecting the critical care doctors to pandemic conspiracy theories
Prosecutors have singled out the case of a 54-year-old with a complex pathology
who they claimed was intentionally killed by a reduction of the norepinephrine level
As numerous experts in the field have since explained
the reduction in that case would have been correct
The two doctors were arrested for 30 days on August 8
but released on August 20 by an appeals court
Health providers came out in solidarity with the arrested doctors
A wildcat strike by workers on the Pantelimon ICU unit
was stopped by a visit of the health minister
the PSD politician is hiding behind the police case
vowing to “respect the investigators’ findings” in what is a “purely criminal case.”
chief of the Romanian Society of Anesthesia and Intensive Care (SRATI)
categorically stated that the two doctors acted correctly and that “murder is absolutely ruled out.” SRATI has asked for the intervention of the ombudsman
for “an analysis of the way in which the right to the presumption of innocence was respected for the persons accused and arrested in the Sf
The Romanian College of Physicians (CMR) publicly slammed the Higher Council of Forensic Medicine (CSML)
the expertise body tied to the prosecutor’s office
The CSML had issued a highly unusual public statement claiming a “99% probability that the death occurred when it did because of the lowering of the norepinephrine level.” The CMR said that the CSML’s statement “gravely violated the doctors’ rights to a fair trial … and made an impermissible condemnation in the public space of the doctors under investigation.”
More than 80 Romanian intensivist physicians working in France signed an open letter expressing solidarity with the doctors and detailing some of the medical and legal challenges of critical care medicine
There remains a large discrepancy between the lack of any evidence of wrongdoing
and the vindictiveness of the prosecutors and the media’s campaign
The “strictly criminal case” is in reality an attack on healthcare workers
The sometimes-unstated conclusion is that the high death count at the hospital is due to the doctors’ criminal actions against their patients
in a bid to “make the unit more effective” and clear the ICU beds for critical cases from the emergency room
accused in the media of “selecting which patient gets to live or die,” with prosecutors calling one of them “the grim reaper.”
A compilation of the World Socialist Web Site's coverage of this global crisis
Designed to obscure and strifle a discussion of the real issues involved
the case is in reality a terrible self-indictment of a criminal ruling class
that doctors are faced with “making the unit more effective,” in order to prevent deaths on the ER floor
is the result of the “forever COVID” policies and the resulting healthcare collapse
The most vulnerable sections of the population are “falling by the wayside,” in the words of Dr
former Director of the (US) National Institute of Allergy and Infectious Diseases
as a result of deliberate policies implemented throughout all the world
While large hospitals such as the Pantelimon and SUUB are on the verge of collapse
pediatric wards are now full of patients year-round
In line with developments across the world
have increased dramatically in recent months
The judicial hounding of the two Romanian healthcare providers is part of an international turn of the ruling class toward lawlessness and authoritarian forms of rule
genocide and war are increasingly incompatible with the maintenance of democratic rights
The prosecution of the two doctors is intended to pollute public life
empower fascistic forces and browbeat healthcare workers into submission
Workers at the hospital are reporting a deluge of threats and harassment
while the life partner of one of the arrested doctors
healthcare workers have initiated workplace struggles against the disastrous conditions in hospitals
The union federations Sanitas and Solidaritatea Sanitara
supported by pseudo-left groups like GAS (Socialist Action Group)
have worked with the government to block impending strikes
It is critical that healthcare workers across Romania take up the struggle to build their own rank-and-file committees, independent of the union bureaucracies, as part of the International Workers Alliance of Rank-and-File Committees (IWA-RFC)
requested on Wednesday the resignation of the manager and medical director of the Emergency Clinical Hospital „Sfântul Pantelimon”
following serious deficiencies in the functioning of the unit and the loss of public trust
The decision comes against the backdrop of ongoing investigations and recent events that have severely affected public confidence in the respective medical facility
as stated by the Ministry of Health in a press release
"Access to quality medical services in emergency hospitals is essential to successfully carry out the reforms and investments implemented by the Ministry of Health
Any behavior or action that jeopardizes these important objectives for the healthcare system is unacceptable," Rafila stated
According to the cited source, the "Sfântul Pantelimon" Hospital was at the center of a major scandal after 17 patients admitted to the Intensive Care Unit died under suspicious circumstances.
The Ministry of Health's Control Body conducted a series of checks and found deficiencies in the management of the situation by the hospital's leadership
The Control Body's report highlighted the lack of effective communication between the hospital's management and medical staff
as well as the need to reassess professional conduct codes
It also emphasized that temporary solutions adopted to manage the crisis
such as using beds from the Emergency Room as a buffer zone for the ICU
The Ministry of Health and the "Sfântul Pantelimon" Hospital have provided the Prosecutor's Office with all the necessary data and documents for the investigation
"The situation at the Sfântul Pantelimon Hospital remains under the supervision of the authorities
and the measures taken will be essential to restore public trust in the healthcare system in Romania," the cited source states
Prosecutors and police conducted searches at the homes of employees of the Emergency Clinical Hospital "Sf. Pantelimon" in Bucharest on Wednesday.
Four medical staff members were brought to the Homicide Department headquarters for questioning
In this case, witness hearings have also taken place, and a medical assistant was detained for false testimony
There are many things that prove negligence
there are many things that should not have happened like this at Pantelimon Hospital
but from them to premeditated murder is an extremely long distance
a board-certified cardiologist and internal medicine physician
Gheorghe Andrei Dan analyzes the dramatic effects
but also the deep causes of the Pantelimon scandal: none of this would have happened or
if the absolutely necessary regulatory systems existed
Due to the generalization and extreme reaction of the media
the patient was pushed into the arms of distrust
And will the ICU doctors still be able to have the freedom of thought
to act knowingly on a seriously ill patient
whom they might eventually save with a last-minute measure
Gheorghe Andrei Dan teaches at the Carol Davila University of Medicine and Pharmacy
and the Interventional Cardiology Laboratory at Colentina Hospital
He was the president of the International Society of Cardiovascular Pharmacotherapy
I have identified three major malignant pillars of the phenomenon:
Violation of the right to presumption of innocence in the absence of direct
Public misinformation through circumstantial arguments
Generalization of conclusions and politicization of the subject
I have also talked about the media noise created during the Covid period around the intensive care units (ICUs)
Many things could probably have been prevented if legislative measures regarding the healthcare system had been taken at that time
I have closely followed everything that appeared in the press as arguments of the prosecution
I have not noticed even a single direct piece of evidence linking the medical act
I am interested in a BBC program that talks about suspicious deaths in hospitals
but where the evidence is of a completely different nature
and some arguments were absolutely ridiculous
For example: "he told me with his eyes to let him die." If this can be considered evidence..
The argument with the infusion pump is concrete but processed in a false way
The infusion rate is confused with the concentration
the same amount of active substance can be contained as in one milliliter per hour
It is not the milliliters/hour flow rate that matters
there is no fixed protocol for the administration of noradrenaline
and noradrenaline is just a small part of a complex therapeutic protocol that is applied to a seriously ill patient
Nowhere does it say that for such a patient
or 5 ml of concentration X of noradrenaline should be given
The treatment is adapted to the conditions and to the patient
The fact that this protocol was not detailed in the medical record is a concrete argument for failure to fulfill service obligations
but it does not in any way demonstrate a causal link to the death
I have repeated to my students and to those who want to listen to me a million times that what is not written does not exist
and the failure to record in the medical record is a type of malpractice
negligence in completing medical documents
She knew she was under scrutiny and was trying to provide an explanation and justification at least for herself
there is no argument that proves the extremely serious accusation of premeditated murder
They represent service negligence and malpractice
but they do not constitute direct evidence to prove premeditation for a criminal act
It should be noted that we are dealing with a section with internal conflicts
what would have been the motive for such an incredible
and unacceptable action by two 30-year-old women working in a state hospital who were not directly linked to the ICU occupancy rate
Especially since they were known to be under observation
because the origin of the whole problem is an old internal conflict section
I am not in a position to determine what competence the nurses had to judge the case from a medical point of view
And the fact that one doctor communicates to another that in his opinion the patient has minimal chances does not make him a criminal if the patient dies from the administered therapy
many things that perhaps should not have happened like this
that no modification of the therapeutic protocol can be made without justification in the record
that verbal instructions cannot be given without being recorded
But from there to premeditated murder is an extremely long distance
Intensive care is the front line in medicine
It is the most pressured of all medical specialties
anonymous heroes and are very few compared to the needs
The exercise in such a continuously intense section strengthens you
makes you not react as you would or even a doctor from another specialty
unless we are dealing with a psychopath and
and a solution like: let's let these people die to empty the ward for someone else
People do not know that intensive care units are very expensive
An ICU bed can sometimes cost as much as a ward
The number of patients cared for by an ICU doctor is much smaller than the number of patients cared for in a regular ward
And something completely different is the terminal patient who
has a very low chance of survival and should be in a palliative care unit
legislation and concrete possibilities do not encourage anything other than vital support until the natural end of hospitalized individuals
I am a bit baffled by the categorical statement: it is causative of death
A temporal link between stopping noradrenaline and death
but without a word about the subject of the discussion - the patient
there is little information about the patient's condition
but they cannot encompass the nuances of all specialties
Among the few things I know concretely from Pantelimon Hospital is that the patient had an extremely severe pathology
Each of them had a great potential for severity
they seemed to indicate a very small chance of success
I have not seen any expert being consulted in an absolutely appropriate manner in the investigation
and I have all the respect for my colleagues from forensic medicine
regarding the statement that reducing noradrenaline in a patient with a blood pressure of 60 is certainly the triggering cause of death
I could write an entire dissertation to prove that it is not so
At least a conditional-optative was necessary
It leaves room for a medical case discussion
Medicine cannot be done by plebiscite; an act of medicine cannot be subject to public vote
You have touched on exactly the sensitive point
if the absolutely necessary regulatory systems for all these layers
for commissions that analyze the severity of cases and extreme solutions existed
There are many administrative and scriptological things that doctors are required to do
The way of treating a palliative care patient in an intensive care unit is different from an acute patient
why the case has become the norm in the medical system and among doctors
Doctors are not the "medical system," but its executive beneficiaries
This confusion is what prompts me to take a stand
And it all started right after generalization and politicization
the issue of "blame shifting" has reappeared: "These doctors are not to be trusted as they defend each other
and the source of all evil is the teaching body."
I doubt that all citizens in Romania can afford to go to Istanbul
put yourself in the shoes of someone who has read all this
Maybe he or a relative needs to be admitted to an ICU where they know they might be intubated
They go as if they were going to the gallows
I accuse you for allowing this to happen."
Mistakes may have been made on the other side as well
the position of the Intensive Care Society and its leaders was correct
They did not embark on a comprehensive analysis of the case but reacted bewildered by the disregard of the presumption of innocence for ..
but they professionally responded to that arithmetic link: the decrease in norepinephrine led to death
the things that have been done cannot be undone
but perhaps they can help us avoid repeating them in the future
I don't think anyone argues that a treatment should not be documented in the observation chart
but everyone was shocked by the accusation of maximum and unjustified severity
but I have a rhetorical question: after all this deafening noise
can we be sure that the judges will make a decision that contradicts what happened
I have a repulsion towards any injustice; I only wish for the judges analyzing this case to be upright
These doctors are dealing with a very hidden and sensitive argument in medical practice
Medical choice is a very complicated matter
There is no set code anywhere that tells you that your choice is unique and correct
Medical choice oscillates between very subjective and very learned things
would have made a decisive decision that could potentially harm the patient but which he considered the only lifesaving measure at that moment
do you think he will still have the courage to do so
I already sense apprehension among my colleagues in the ICU
fear of making decisive decisions that could expose them
Will ICU doctors still have the freedom of thought
to act with full knowledge in the case of a critically ill patient
whom they might save with a last-minute measure
The consequences of this phenomenon go beyond its resolution and are very serious
This is the main reason why I took a stand
and the fact that the patient was involuntarily pushed into the arms of distrust
The interview transcript was conducted using the Vatis Tech application
Metrics details
This study clarifies the problem of decongestion in quantum networks
with a specific focus on the crucial task of entanglement distribution
Entangled particles are a valuable resource in quantum networks
as they are used for most quantum protocols
ensuring that nodes in quantum networks are supplied with entanglement efficiently is mandatory
parts of a quantum network are contested by multiple entanglement resupply processes and the distribution of entanglement becomes a challenge
The most common network intersection topology
the star-shape and it’s various generalizations
in order to achieve optimal entanglement distribution
The analysis is comprehensive and relies on rigorous mathematical calculations which aids in selecting the most appropriate strategy for different scenarios optimally
is preserved only if the system does not have any interaction with the environment
to be able to successfully transport entangled particles over long distances with high fidelity
the system should interact as little as possible with the environment while maintaining the ability to be manipulated and measured
a great effort is put towards avoiding the physical transportation of e-pairs
These limitations come in part from the fact that quantum signals cannot be amplified
as doing so would disturb the quantum state
leading to a loss of entanglement fidelity
a route between two nodes requesting entanglement can be found
and by making use of entanglement swapping
segments of a route can be effectively traversed in parallel
leading to a decrease in the total distance a particle has to travel
as well as lowering the total transmission time
where each node had a dedicated link toward it’s associated node
an efficient method to effectively decongest entanglement distribution networks would be critical
This stems from the fact that there is a multitude of protocols that require entangled pairs
Having a lower throughput of e-pairs due to congestions in the network may lead to lower robustness of the protocols employed
as quantum error correction protocols can benefit from a higher throughput of e-pairs
the scalability of a global quantum internet is directly impacted by the efficiency of the entanglement distribution network that supplies the e-pairs to the end users
which proposes an algorithm that increases the throughput of a quantum network by always picking the path that guarantees the highest distribution rate and using the remaining resources to create backup paths
Their work emphasises that in order to increase the throughput of a quantum network
one needs to increase the success rate of the transmission
while also increasing the transmission speed by using methods such as entanglement swapping
they have transposed the problem as two linear programming problems
they are able to achieve better expected time than previous algorithms
while retaining a small computational overhead for determining the routes
we consider a scenario where there is only one link between nodes
that can transmit only unidirectionally at a given time
We also assume there is a certain duration \(\tau _t\) which models the transmission time throughout the network
we can assume that \(\tau _t = \max {\tau _i}
each with a transmission time of \(\tau _i\)
Since we make use of entanglement swapping
we can consider a \(time\text { }slot\text {}\tau \) as the transmission time through one link and the time associated to a subsequent measurement \(\tau _m\)
\(time\text { } slot\) can be described by the following equation
Network topology of concurrent entanglement distribution
and Charlie and Dave have requested e-pairs at the same time
as both networks need to pass an e-pair through it
Throughout this work an analysis regarding how to decongest simultaneous entanglement resupply requests within the same network is presented
Due to the nature of quantum entanglement and the procedures such as entanglement swapping
we cannot serve requests simultaneously through the same node or link
We can however decongest the network through the proposed strategies
While the case where the routes do not intersect is trivial
for the case where there is concurrency for the nodes
described and compared in the following sections
determining under which conditions each of them should be used
Starting with the scenario where within one time slot
an entanglement request is served between two nodes: Alice and Bob (A
by using a chain of \(l+1\) nodes (including Alice and Bob) connected with l quantum links
we maximize the success probability for each time slot by performing the minimum amount of Bell measurements
All nodes situated on even positions (including Bob
when l is odd) should generate an e-pair and send one qubit in the direction of Alice and one in the direction of Bob
is given by \(P_{chain} = p^l*q^{\lfloor \frac{l-1}{2}\rfloor }\)
where \(p^l\) is the probability of all l transmissions working successfully
\(\lfloor \frac{l-1}{2}\rfloor \) is the number of Bell measurements performed
and therefore \(q^{\lfloor \frac{l-1}{2}\rfloor }\) is the probability of all those measurements being successful
A more interesting situation appears when two simultaneous entanglement requests are received: (A, B) and Charlie-David (C, D), and their selected paths intersect, as in Fig. 2
We will first look at the case when both the paths from A to B and from C to D have a length of 5 nodes and are intersecting in the middle node
We will first propose two strategies to solve this scenario
and then analyze when each one should be used
Network topology with the two possible distribution approaches; (a) represents the symmetrical approach
where on both routes the entanglement is generated and measured at the same node indices; (b) represents the asymmetrical approach
On one of the route, the second and fourth nodes generate an entangled pair, while on the other route the first, third, and fifth nodes do so (see Fig. 3b). In other words, a route uses Even Generation, while the other uses Odd Generation of entanglement. All those nodes then send one qubit to each of their neighbouring nodes on their respective routes.
After calculating the expected performance of both strategies, we obtain
Using these values we can compute the optimal strategy based on the probabilities p and q and, as expected, we can see from Fig. 4 that the asymmetrical approach performs better when the probabilities are high
This stems from the fact that it offers the possibility for both requests to be solved simultaneously
while the symmetrical approach is better for lower probabilities because it’s at a disadvantage only when all 8 transmissions are successful
In this section we generalize the previously discussed network topology proposing new optimal entanglement distribution strategies
We want to emphasise that we consider the star-shaped network without loss of generality
as a subgraph resulting from intersecting routes between nodes in a graph
This generalized star topology would either have longer spokes
have more than one node as the intersection between the spokes
In this section we will analyse the effect of the first two of the variants separately
and the case where the intersection is a chain of multiple nodes
We will not consider any backup routes between the pairs
We will assume that the two lengths (in number of edges) are \(l_1\) and \(l_2\), with \(l_1 \le l_2\). If all transmissions are successful on both paths, the intersection node should choose to perform entanglement swapping on the qubits belonging to the longer path, the one with length \(l_2\). The expected number of required time slots required for the symmetrical approach to satisfy both entanglement requests regardless of the lengths of the paths will then be given by
Since this distribution scheme is only used when both length are even, in order to simplify the equation we will assume that both \(l_1\) and \(l_2\) are even. Therefore, by calculus we obtain
Let the two lengths (in number of edges) be \(l_1\) and \(l_2\)
We will use a variation of the Asymmetrical approach where we have to choose which of the two paths will perform the extra BSM
It turns out it is always optimal for the shorter path to perform the extra BSM
we will obtain the expected number of time slots required to entangle both requesting pairs from
By assuming that \(l_1\) and \(l_2\) are even
Optimal number of \(Even\text { } Distributions\) in the context of many intersecting routes
we assume that there are more than 2 pairs requesting entanglement
with only one node as the intersection between their respective routes
we consider the lengths of the spokes to be 2
We will consider again two possible generation schemas - even and odd
Since the center node can generate as many e-pairs as needed at the beginning of every distribution attempt
each path using the odd schema will have an independent probability of success of \(p_o = p^4q^2\)
as the intersection node isn’t able to perform more than one BSM per timeslot
we obtain that when i paths use the even schema
the probability of at least one of them succeeding is equal to \(p_e^i = (1 - (1 - p^4)^i)q\)
What remains is finding how many pairs should use each of the two schemas for the optimal distribution
the expected number of timeslots required to serve n requests for some fixed probabilities p and q
The values of \(t_n\) can be calculated recurrently by choosing the optimal number of paths to use the even schema
i represents the number of paths using the even generation schema
the goal is finding the i that results in the smallest expected number of time slots required
We observe that regardless of the probabilities p and q
the value of i that minimizes the expected time is always equal to the one that maximises the expected throughput for every single timeslot
the expected number of pairs served within a timeslot out of n requesting pairs while using the even schema for i of the paths
and the odd schema for the remaining \(n-i\)
By substituting \(p_e^i\) and \(p_o\) and maximising \(\mu _n^i\) in the above equation we will obtain \(i_{opt}\)
the number of paths that should use the even generation schema
the relatively few values that are associated for high p and q values can be observed through the visible steps that the surface has
the optimal number of even schemas remains relatively low
if the chances of successful distribution are low for both schemas
it is better to focus resources on getting at least one e-pair transmitted
through the most reliable method of the two
In Algorithm 1 we outline the step-by-step process for selecting the optimal method for distributing entanglement in a multiple request scenario
This approach takes into account the specific parameters of the intersection
providing a sysematic way to determine the best course of action
any outbound or inbound pairs would have to travel between the ends of the chain
This would imply that between all the consecutive nodes in the chain
Both approaches have their merits, and, as we have shown, their usecases. The symmetrical approach works best when the probability of transmission is fairly low through the optical links of the network. Even though only one of the requesting pairs can be served within a time slot, this way, we can maximize the chance that at least one of the pairs gets entanglement. Thus, the symmetrical method is the most resilient of the two approaches to low quality transmissions through the network.
The main advantage of the asymmetrical schema is that it has the potential to simultaneously serve two pairs within a single time slot. However, due to the nature of odd generation of entanglement, this results in one more BSM than the symmetrical variant, leading to a lower chance of overall success. This distribution schema would be preferred to maximize throughput in networks with high transmission and measurement probabilities.
Intersecting chain of two entanglement distribution routes
We have analyzed the effectiveness of these strategies through more generalized intersections
such as star shaped topologies with long spokes
We have found that the asymmetrical schema is still viable with longer spokes
albeit with smaller tolerances for successful measurement and transmision
We have also described the equation that gives the optimal distribution of even and odd generations for more numerous requesting pairs
such that we can serve the most number of pairs in the least amount of time slots
we have concluded that with more nodes at the intersection
we cannot perform an asymmetrical distribution
thus we can only deliver a maximum of one e-pair per timeslot
we propose an analysis of strategies over an even more general star-shaped network topology
An analysis of different types of topology like crossbars and other interconnection networks
and the effect of backup routes upon these distribution schemas
The datasets generated during the current study and the complete mathematical calculus will be made available from the corresponding author on reasonable request
Can quantum-mechanical description of physical reality be considered complete?
Yin, J. et al. Bounding the speed of spooky action at a distance. arXiv preprintarXiv:1303.0614 (2013)
How deep the theory of quantum communications goes: Superadditivity
Quantum internet: Networking challenges in distributed quantum computing
Towards a distributed quantum computing ecosystem
Distribution of controlled unitary quantum gates towards factoring large numbers on today’s small-register devices
Teleporting an unknown quantum state via dual classical and Einstein–Podolsky–Rosen channels
25 years of experimental quantum teleportation
Quantum teleportation with one classical bit
Simple proof of security of the bb84 quantum key distribution protocol
The security of practical quantum key distribution
Nielsen, M. A. The entanglement fidelity and quantum error correction. arXiv preprintarXiv:quant-ph/9606012 (1996)
Theory of control of the spin-photon interface for quantum networks
Satellite-based photonic quantum networks are small-world
Nonclassical interference and entanglement generation using a photonic crystal fiber pair photon source
No second law of entanglement manipulation after all
Nondestructive detection of photonic qubits
Long-distance free-space quantum key distribution in daylight towards inter-satellite communication
Twin-field quantum key distribution over 830 km fibre
Quantum key distribution over a channel with scattering
Experimental investigation of criteria for continuous variable entanglement
“Event-ready-detectors” bell experiment via entanglement swapping
Purifying noisy entanglement requires collective measurements
Experimental entanglement swapping: Entangling photons that never interacted
Purification via entanglement swapping and conserved entanglement
Opportunistic entanglement distribution for the quantum internet
Entanglement-gradient routing for quantum networks
Routing space exploration for scalable routing in the quantum internet
Entanglenetsat: A satellite-based entanglement resupply network
Entanglenet: Theoretical reestablishment of entanglement in quantum networks
Quantum repeaters: The role of imperfect local operations in quantum communication
Experimental quantum repeater without quantum memory
Quantum teleportation of a polarization state with a complete bell state measurement
Arbitrarily complete bell-state measurement using only linear optical elements
Optimal entanglement swapping in quantum repeaters
Efficient quantum network communication using optimized entanglement swapping trees
Dynamics of entangled networks of the quantum internet
Concurrent entanglement routing for quantum networks: Model and designs
In SIGCOMM’20: Proceedings of the Annual conference of the ACM Special Interest Group on Data Communication on the applications
Multi-entanglement routing design over quantum networks
In IEEE INFOCOM 2022-IEEE Conference on Computer Communications
3/4-efficient bell measurement with passive linear optics and unentangled ancillae
Ancilla-assisted linear optical bell measurements and their optimality
Download references
This work has been partially supported by RoNaQCI
This work is dedicated to Professor Vasile Preda in commemoration of his 75th birthday
Computer Science and Engineering Department
Bogdan-Călin Ciobanu & Pantelimon George Popescu
P.G.P.; writing–original draft preparation: L.P.V.
and P.G.P.; writing–review and editing: B.C.C
and P.G.P.; supervision: P.G.P.; All authors have read and agreed to the published version of the manuscript
The authors declare no competing interests
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations
Reprints and permissions
Download citation
DOI: https://doi.org/10.1038/s41598-023-36562-x
Anyone you share the following link with will be able to read this content:
a shareable link is not currently available for this article
Sign up for the Nature Briefing: AI and Robotics newsletter — what matters in AI and robotics research
Metrics details
Nowadays QKD plays a critical role in unconditionally-secure and quantum-safe key distribution
Commercially available QKD devices are getting more popular for institutional and governmental national and international networks
but are expensive and offer limited key rates
We provide a formalization of QKD-generated key forwarding and redistribution at the KMS level by extending the network graph of physical QKD links to the complete graph with logical links
and we investigate its application on three practical scalable scenarios (all-to-all
We define a maximization goal for each scenario
and provide a linear programming problem statement to compute the optimal redistribution
We perform an extensive analysis of the algorithm in terms of forwarding results and key consumption on simulated QKD networks and discuss the implications of network size and graph topology on the algorithm’s performance and complexity
since key re-distribution only concerns the actions of the end-users
we considered the edges of the graph as representing a link between two end-users and we ignored the practical realization of this links in terms of the physical layer and the number of repeater segments
Each QKD link between two end-users Alice and Bob is composed of two QKD devices
one located on the premises of Alice and one located on the premises of Bob
The devices exchange quantum information to generate a series of pairs of identical bit sequences (keys)
which can be accessed by both end-users and which are guaranteed to be unconditionally secure
The typical workflow is as follows: Alice requests a 256-bit key from her QKD device through the vendor-specific application-programming interface (API) built into the device; the API responds with the contents of the key and a public key ID; Alice sends this key ID to Bob over any public channel (for example
via Internet); Bob submits the key ID to his device’s API
which responds with a key identical to Alice’s
Now Alice and Bob hold the same key obtained in an unconditionally secure manner
which they can use to encrypt further communication
Unlike classical key exchange algorithms which can never be proven secure but rely on assumed security due to having withstood significant scrutiny and attempts to break it
QKD is proven to achieve perfect unconditional security and perfect forward secrecy in the key exchange mechanism
The motivation for having these security properties obviously persists in the case of key exchange between end-users across multiple links
a network may consist of three end-users: Alice (A)
with QKD links between A–B and between B–C
A key forwarding mechanism implemented at Bob can be used to obtain keys with the same security properties between A–C
A way this can be achieved in practice is as follows: 1
One key is generated on each link (a key \(K_{AB}\) between Alice and Bob
and a key \(K_{BC}\) between Bob and Charlie); 2
encrypts \(K_{AB}\) using \(K_{BC}\) as a key
with a quantum-safe encryption algorithm which ensures unconditional security
Bob then sends this encrypted key to Charlie via Internet
Now both Alice and Charlie hold the same key \(K_{AB}\)
and they can use it for further unconditionally secure communication
In this work we address the issue of equitable key generation in a complex network
and we provide an algorithm that identifies the optimal key distribution strategy which loses the minimum amount of keys while achieving a distribution goal across one of several scenarios
The goal is to maximize the key rate across a given set of target links (as defined in the scenarios section below). The equitability property of redistribution refers to the act of ensuring that key rate is redistributed equitably among the nodes. This is achieved through a careful selection of the metric to maximize: the protocol maximizes the minimum key rate along any of the target links.
We define the following main scenarios with practical applicability.
Balanced Scenario: An example of the balanced scenario \(S_{A2A}\): a 4-node star network where every pair of nodes is part of the target group
The left side of the figure presents the original network configuration; the right side presents the optimal key rate obtained by applying the algorithm configured in the balanced mode
The global minimum key rate has the maximum possible value of 33
All-to-All (Balanced) Scenario (\(S_{A2A}\))—see Fig. 1: this scenario is applicable to a federated QKD network where all end-users are equal and there is no preferential set of nodes
Each end-user would like to have a key rate that is as high as possible with all other nodes
without taking a significant toll on the overall key generation rate of the network
An example of balanced network is provided
where the desired behaviour is to maximize the minimum key rate between any pair of two nodes
either directly connected with a physical link or not (the logical links are displayed in red)
Broadcast Scenario: An example of the broadcast scenario \(S_{O2A}\): a 7-node network where the goal is to maximize the key rate exchanged between node B (marked in red) with every other node in the network
The minimum broadcast key rate has the maximum possible value of 50
High-throughput Scenario: An example of the high-throughput scenario \(S_{O2O}\): a 9-node network where the pair B–F must exchange keys with a rate as high as possible at the expense of the key rate between any other pair of nodes
The obtained key rate between B and F is at the optimal value 205
The main structure is the network’s complete undirected graph \(G = (V
c)\) where: V is the ordered set of vertices
each node corresponding to a QKD end-user; E is the set of edges
each edge corresponding to a (physical or logical) link between two end-users; \(c: E \rightarrow \{black
The color of the edge represents its type (black edges are physical
red edges are logical); \(w: E \rightarrow \mathbb {R}^+ \cup \{0\}\) is the edge weight function
The weight attached to each edge represents the key rate exchanged between the connected nodes
black links have a weight that is equal to the measured continuous key rate between the QKD devices at the ends of the link
while red edges have a weight of 0 (there is no key exchange if nodes are not directly connected physically)
After the optimization algorithm is applied
the output consists of a redistribution map for each physical links
key rate) of both black and red edges as per the scenario and the optimization rules
the target set contains all links in the complete graph: \(T = E\)
the target is the set of all links between the given target node t and every other node: \(T = \{ (t
the target contains one single link between the two target nodes as defined in the scenario: \(T = \{(t_1
We formalize the concept of “balanced” weight redistribution by a careful selection of the metric to maximize: the optimization goal is to maximize the value \(n = \min _{\tau \in T} w(\tau )\)
We formalize weight redistribution as follows
we consider without loss of generality that keys flow (i.e
get forwarded) from \(t_1\) to \(t_2\) if \(I_{t_1} < I_{t_2}\) where \(I_v\) is the index of node v in V
Keys may flow from \(t_1\) to \(t_2\) along any path in \(P = \{ \text {path from } t_1 \text { to } t_2 \}\) that passes only through black edges
Assume that in (one of) the optimal distribution(s)
k bits of key rate flow from \(t_1\) to \(t_2\) along a path of length L \(p = \{(t_1
Since key forwarding implies the key bits cannot be re-used by any of these links
this is equivalent to reserving k key rate bits in each of the links that are part of path p specifically for the target \(\tau = (t_1
we define the redistribution function \(r: T \times E_{black} \rightarrow \mathbb {R}^+ \cup \{0\}\) which maps each combination of target \(\tau \in T\) and physical edge \(e \in E \,\text {such that}\
c(e)=black\) to the number of key bits per second generated along e that are reserved for target \(\tau\)
To align the output of the algorithm with the practical requirements of a KMS
we further define weight redistribution based on nodes rather than edges
for each node v we define two distribution functions \(r^v_{in}: T \times \{(v
u) \in E_{black}\} \rightarrow \mathbb {R}^+ \cup \{0\}\) and \(r^v_{out}: T \times \{(v
u) \in E_{black}\} \rightarrow \mathbb {R}^+ \cup \{0\}\) for the forwarding of keys through v from and to neighboring nodes
with the important property of key conservation per node: \(\forall \tau \in T \sum _{(v,u) \in E_{black}} r^v_{in}(\tau
(v,u)) = \sum _{(v,u) \in E_{black}} r^v_{out}(\tau
\(t_1\) is a key source (\(r^{t_1}_{in}(\tau
while \(t_2\) is a key drain (\(r^{t_2}_{out}(\tau
for key conservation per edge we need to impose the rule that \(r^v_{in}(\tau
the goal of the present research is to provide an optimal set of functions \(r^v_{in}\) and \(r^v_{out}\) for every node v which maximize the metric n along the set of targets as selected in T
We stress the fact that T may contain any combinations of links in E
and \(S_{O2O}\) are only defined for more accurate comparison with practical situations in QKD networks
Linear programming is a modelling technique for maximizing (or minimizing) the value of an objective function linear in any number of lower bounded parameters based on a list of linear constraints (equations and inequalities) on said parameters. The list of linear constraints define a multidimensional convex polytype over which the function is optimized, which is proved to guarantee optimality.
Converting the rules as defined in the formalization section into LP formalism following the multi-commodity flow problem’s solution, we obtain the constraints in Algorithm 1 (marked C in the pseudocode). The meaning behind each constraint type is explained below:
C1: if \((t_1, t_2), t_2>t_1\) is a potential target, then \(t_1\) is a key source (it does not have any redistribution inputs)
C2: if \((t_1, t_2), t_2>t_1\) is a potential target, then \(t_2\) is a key drain (it does not have any redistribution outputs)
C3: if \(\tau = (t_1, t_2)\) is a potential target and (X, Y) is a link through which redistribution for \(\tau\) may potentially be done, then the input of node X from node Y for target \(\tau\) is equal to the output of node Y to node X for target \(\tau\) (flow reversibility)
C4: for every link (X, Y), the sum of all key forwarding rates along this link regardless of target must not exceed the physical key rate capability of the link
C5: for every potential target \(\tau = (t_1, t_2)\) and every node X, the sum of all inputs of X for target \(\tau\) must be equal to the sum of all outputs of X for target \(\tau\) (key conservation along flows from \(t_1\) to \(t_2\))
C6: for every potential target \(\tau = (t_1, t_2)\), if \(\tau \in T\) according to desired scenario then we impose the goal that the resulting key rate between nodes \(t_1\) and \(t_2\) must equal or exceed the metric n to be maximized (as this is the optimization goal: maximizing the minimum key rate between the nodes of any target pair).
The evolution of performance parameters as the network size increases along 15,000 runs on randomly generated graphs of 3–40 nodes with 0–15 redundant links
(a): Optimal n maximized in a random graph network by number of nodes
X Axis: Number of nodes; Y Axis: Average optimal n
(b): Evolution of average outcome key rate exchanged between all node pairs \(\tau\) in T
X Axis: Number of nodes; Y Axis: Average key rate
(c): Evolution of key consumption for target optimization as a percentage of initial total network-generated key rate by number of nodes
X Axis: Number of nodes; Y Axis: Key consumption as a percentage of total
We analyze the resulting optimal key rate redistribution which achieves the highest minimum n across every target node pair
The analysis is performed in three different scenarios with practical applicability: all-to-all (every pair of nodes in the network is a target)
one-to-all (all pairs made out of a specific fixed node and every other node)
and one-to-one (one specific pair is the only target)
The evolution of key rates between target nodes by number of nodes along 5000 runs per scenario on randomly generated graphs of 3–40 nodes with 0–15 redundant links
plotted with the initial key rates for comparison
average outcome key rate between targets and average intial key rate between targets for (a): all \(S_{A2A}\) runs
(b): top 25% percentile of key rates in \(S_{A2A}\) runs
(c): top 50% percentile of key rates in \(S_{A2A}\) runs (d): top 75% percentile of key rates in \(S_{A2A}\) runs
the average key rate between the two target nodes
For the \(S_{O2A}\) scenario: (f): top 25% percentile of key rates; (g): top 50% percentile of key rates; (h): top 75% percentile of key rates
Analysis of algorithm complexity and discussion of performance metrics by network topological factors
(a): Algorithm running time by number of symbols in the LP problem statement
(b): Evolution of number of LP symbols by network size per scenario
(c): Optimal n by graph betweenness centrality in \(S_{A2A}\) scenario
(d): Ratio of average outcome target key rate and average initial key rate by graph betweenness centrality in \(S_{A2A}\) scenario
(f): Average outcome target key rate and optimal n by graph diameter
(g): Ratio of outcome average key rate to initial average key rate by graph diameter
(h): Average outcome key rate by graph degree centrality per scenario
and we observe it is proportional to \(|V|^2\) for the one-to-one scenario (two symbols per node pair)
to \(|V|^3\) for the one-to-all scenario (two symbols per node pair per target
where the number of targets is proportional to number of nodes)
and to \(|V|^4\) for the all-to-all scenario (two symbols per node pair per target
where the number of targets is proportional to number of nodes squared)
The results indicate that the more close together a graph is (smaller diameter
the more spread apart a graph is (larger diameter
a line graph where the path between the most extreme nodes passes through all other nodes)
This observation is easily explained by the fact that larger diameter implies more pairs of nodes for which the redistribution flows through the same bottleneck paths
Considering networks with no redundant links (i.e
a graph with smaller diameter (for example
a star topology with a single central node connected to all others) may produce a higher key throughput in the balanced and broadcast scenarios
whereas line-like topologies may cover a larger terrestrial area
at the expense of lower optimal n in these scenarios
Another observation is that the outcome average key rate between the targets increases when the optimal n decreases
since lower redistribution also means lower key consumption rate
In this work we introduce the relevant concepts in QKD-generated keys secure forwarding using OTP and motivate the need for this given the security requirements and the low key rate of commercially available QKD devices
We introduce the graph mathematical formalism that we use to model QKD networks and to extend the network graph to the complete graph using logical links between all nodes that are not physically connected with QKD infrastructure
We provide a multi-commodity flow statement of the problem
and three scenarios with practical applicability in typical QKD use-cases
We give a description in LP syntax which we run and analyze on 16,250 total simulated networks of up to 40 nodes and 15 redundant links
providing a thorough investigation on the algorithm results and performance as well as the impact of graph size and topology
we note that with this approach we can tackle any kind of QKD network key forwarding problem in the same formalism
including optimal addition of QKD physical links and the generation of goal-oriented time-based forwarding schedule
The simulation code and the datasets generated during the current study will be made available from the corresponding author upon reasonable request
Cerberis XG QKD System. https://www.idquantique.com/quantum-safe-security/products/cerberis-xg-qkd-system/
Algorithms for quantum computation: Discrete logarithms and factoring
In Proceedings 35th Annual Symposium on Foundations of Computer Science
Multicarrier continuous-variable quantum key distribution
Fast and secure routing algorithms for quantum key distribution networks
In 2022 14th International Conference on Communication Systems & NETworkS (COMSNETS)
Resource allocation in a quantum key distribution network with leo and geo trusted-repeaters
In 2021 17th International Symposium on Wireless Communication Systems (ISWCS)
Mathematical model and topology evaluation of quantum key distribution network
An efficient routing protocol for quantum key distribution networks
A routing method designed for a quantum key distribution network
In 2016 Eighth International Conference on Ubiquitous and Future Networks (ICUFN)
A novel protocol for multiparty quantum key management
Architecture of multicast centralized key management scheme using quantum key distribution and classical symmetric encryption
Key management systems for large-scale quantum key distribution networks
In Proceedings of the 18th International Conference on Availability
Secure and efficient key management technique in quantum cryptography network
In 2012 Fourth International Conference on Ubiquitous and Future Networks (ICUFN)
Quantum key distribution: A networking perspective
Linear programs for entanglement and key distribution in the quantum internet
Entanglement distribution in a quantum network: A multicommodity flow-based approach
Cost-efficient quantum key distribution (qkd) over wdm networks
Time-scheduled quantum key distribution (qkd) over wdm networks
The engineering of a scalable multi-site communications system utilizing quantum key distribution (qkd)
Faster approximation schemes for fractional multicommodity flow problems
Approximating fractional multicommodity flow independent of the number of commodities
Download references
This work is dedicated to professor José Luis Díaz-Barrero on his 70th anniversary
National University of Science and Technology POLITEHNICA Bucharest
Alin-Bogdan Popa & Pantelimon George Popescu
and P.G.P; supervision: P.G.P; all authors have read and agreed to the published version of the manuscript
Reprints and permissions
Download citation
DOI: https://doi.org/10.1038/s41598-024-64994-6
has launched the first green station at the cora Pantelimon hypermarket in Bucharest
a pilot program that is part of the company’s commitment to promote a circular economy model
The green station is the result of Cora’s partnership with two well-known companies in the field of environmental protection programs, Fepra and Envipco. The investment in this first project is EUR 100,000.
Head of Environmental Issues at cora Romania: “cora encourages the population to be actively involved in recycling
The green station makes this process very accessible
You come to Cora’s shopping and before you enter the store
stop by the green station in the parking lot
It is also possible to recycle household appliances and batteries
a voucher is issued that can be used for shopping in all cora hypermarkets
we have launched a process of educating employees and
but we hope that in time recycling will become a habit
The reward received for each recycled waste is 5 bani
The cora green station differs from other existing solutions on the market in that it makes it possible to recycle used electrical equipment (stove, hair dryer, iron, etc.), and in the future will include other flows such as textile waste or reusable packaging.
said that this is the first of a network of recycling stations that will be made by the Minister at national level
”We have EUR 400 million through PNRR, European funds, and one of the projects is to create a national network of recycling stations. This national infrastructure is a solution for reaching recycling targets and also for increasing the reuse of all the waste,” said Tanczos Barna.
Objective: collection of 12 tons of waste / month
over 900 kg of aluminum waste and 300 kg of cardboard
The monthly collection target set for Cora Green Station is 12 tons of waste or about 160,000 units
The waste is handed over to an authorized collection center
from where it is sent to specialized factories
where it is subjected to the recycling process
reach Cadelplast (FEPRA Recycling) in Hunedoara or Greentech in Buzau
where the bottles are transformed into pet flakes
then to another factory they are transformed into granules from which new PET containers will be produced
Metrics details
Factoring a 2048-bit number using Shor’s algorithm
it is well known that there is yet much time before we will have this many qubits in the same local system
This is why we propose a protocol for distributed quantum computation applicable to small register devices
specifically for the distribution of controlled unitary gates
the key element in the construction of every quantum computation algorithm
We leverage quantum sharing of partial results to obtain a parallel processing scheme
allowing for the first time the quantum distribution of very large gates with thousands of inputs using only small register devices with tens of qubits
we improve all previous controlled unitary gate distribution approaches
The impact is quantified for recent milestone hardware realizations of quantum processors
The security of the communication protocols of tomorrow is thus heavily influenced by the advent of quantum computing
itself a far cry from the 5-7 qubit systems freely available in the cloud
Multipartite distribution of N-qubit quantum functions9
the point of both protocols is not to circumvent register size limits
but rather to allow the processing of non-local data
and as such they both make use of a local copy of the gate
to distribute a N-control Toffoli gate in this way
Improved multipartite distribution of N-control unitaries12
this black-box approach offers no particular insight as to how many small-register systems are required to efficiently run a workload requiring full connectivity
in this paper we set out to provide the first protocols for the distribution of N-control Toffoli gates using only small register devices
Throughout this paper we consider a logical quantum system comprised of N control qubits
\(C_1,\,\dots ,\,C_N\) and M target qubits
The N control qubits are split across K local physical quantum systems
while the M target qubits are consolidated in a single local physical quantum system
These \(K+1\) local physical systems also include ancillary qubits used for entanglement distribution as well as computation
we denote by \(N_i\) the number of controls at site \(S_i\) for \(1\le i\le K\) and relabel them \(C_{1}^{(i)},\,\dots ,\,C_{N_i}^{(i)}\)
On top of these \(K+1\) local physical systems we overlay a communication oriented tree
where \(V=\left\{ S_1,\,\dots ,\,S_{K+1}\right\}\)
with the tree rooted at the target site \(S_{K+1}\)
we assume that the nodes are labeled in reverse breadth-first order
we reduce our construction to a single parameter
and all internal nodes will have exactly B children
which may have fewer if the number of nodes is insufficient for them all to have B children
for a balanced binary tree with \(K=5\) control systems
the target system has index \(S_6\) and communicates with \(S_5,\,S_4\)
where \(S_5\) communicates with \(S_3,\,S_2\) and \(S_4\) communicates only with \(S_1\)
Parallel cascade distribution of controlled unitaries
The circuit equivalence in Fig. 3 holds
We provide a proof by induction, following a chain of circuit equivalences aided by Fig. 2
This distributes the entire controlled unitary gate targeting \(S_{K+1}\)
decomposing it into \(1\le b_{K+1}\le B\) (possibly non-local) Toffoli gates each targeting one of the \(b_{K+1}\) systems \(S_{a_{K+1}+j}\)
with the first \(b_i\) sets acting non-locally
and the local \({\textbf{U}}\) gate acting on the target and local controls in \(S_i\)
This distributes this nonlocal Toffoli gate controlled by the controls in \({\hat{P}}_i\) and \(S_i\) and targeting \(O_{i}^{(i)}\)
decomposing it into (possibly non-local) \(1\le b_{i}\le B\) Toffoli gates
each targeting one of the \(b_{i}\) systems \(S_{a_{i}+j}\)
Notice that this perpetuates the induction assumption
hence at the end of this process all of the gates are local
Now, at the end of this process, the final circuit equivalence takes the form shown in Fig. 3
The main insight of this paper is that not all K controls in a fully non-local K-control Toffoli gate need to be brought together
each site can compute and store the partial sum of one or more subsets of bits
site i receives from site \(i-1\) the product of the first \(i-1\) bits
This allows us to distribute the K-qubit Toffoli gate over a network comprised only of 3-qubit systems
at the cost of execution time numerically equal to K
in a tree topology with uniform branching factor \(B\ge 2\)
site i receives from subordinate sites \(i_1,\,\dots ,\,i_B\) the product of their assigned bits
and sends the result forward to its superior
This allows us to distribute the K-qubit Tofffoli gate over a network comprised only of \((B+2)\)-qubit systems
at the cost of execution time \(\log _B K\)
the execution time is logarithmic: \(\log _{B+2} K\)
and when the execution time is required to be a fixed constant t the qubit count is a fractional power
The circuit equivalence in Fig. 4 holds
This immediately follows from the equivalence in Fig. 3 setting \(B=1\). \(\square\)
Cascade distribution of controlled unitaries
the time required for the execution of the gate is equal to the depth of the graph
If each site except the sources has an inner degree \(B\ge 2\)
We can also present this protocol in the form of a distributed algorithm
specifying the actions at each of the local sites \(S_i\)
as shown in Algorithm 2 where all internal nodes \(S_1,\,\dots ,\,S_K\) execute procedure ParInternalNode and the root \(S_{K+1}\) executes ParFinalNode
to implement a non-local N-control Toffoli gate when all systems have n qubits we find \(K=\lceil \frac{N+1-B}{n-B-1}\rceil\)
using this protocol we can implement such a gate controlled by \(N=400,000\) qubits using 200
in execution time \(18\tau\) where \(\tau\) is the time required for a node’s computation (i.e
the local Toffoli and Hadamard gates and communication with neighbors)
one can use 16,667 27-qubit IBM Falcon systems
DiscussionIn this subsection we will compare the existing distribution algorithms with the presented one in terms of execution time
as well as number of entanglement pairs consumed
we will discuss the applications and implications of the improved distribution algorithm
our protocols greatly reduce the requirement on local subsystem dimension
either to its square root while maintaining constant time
or even to a constant but at the cost of logarithmic time
the protocols presented in this paper compare favorably to the state of the art
greatly reducing restrictions on local system dimension
if all quantum operations in Shor’s algorithm such as modular exponentiation were to be decomposed as products of controlled unitaries
with a logarithmic (18x) increase in execution time
we could run Shor’s algorithm to factor 2048-bit numbers using 200,000 5-qubit systems
This highlights the impact of future work related to the distribution of not just controlled unitaries
but actual quantum functions such as fast modular exponentiation which could lead to the experimental implementations of Shor’s algorithm distributed across a network of small registry devices
For future work we propose the analysis of the noise introduced by entanglement distribution across a network with tens of thousands of quantum computers
for example considering computation fidelity when using only diluted EPR states
it is not clear how this compares to how noise scales in large-scale quantum computers with hundreds of thousands of qubits
The datasets generated during the current study will be made available from the corresponding author on reasonable request
National Institute of Standards and Technology 2016)
Building a superconducting quantum computer. Invited Talk PQCrypto 2014, October 2014 Waterloo, Canada. https://www.youtube.com/watch?v=wWHAs--HA1c Accessed: 2022-10-25
Nist status update on the 3rd round (Cryptography Technology Group
National Institute of Standards and Technology
In Proceedings 35th annual symposium on foundations of computer science ( IEEE
Resource analysis of quantum computing with noisy qubits for Shor’s factoring algorithms
IBM quantum breaks the 100-qubit processor barrier
Distributed quantum computation based on small quantum registers
Optimal local implementation of nonlocal quantum gates
Non-local quantum functions and the distributed Deutsch-Jozsa algorithm
Quantum teleportation of shared quantum secret
Distributed quantum computation assisted by remote Toffoli gate
In International Conference on Cloud Computing and Security
A general protocol for distributed quantum gates
Cuomo, D. et al. Optimized compiler for distributed quantum computing. arXiv preprint arXiv:2112.14139 ( 2021)
IBM quantum processor types. https://quantum-computing.ibm.com/composer/docs/iqx/manage/systems/processors
Download references
David Constantinescu & Pantelimon George Popescu
P.G.P.; writing—original draft preparation
P.G.P.; All authors have read and agreed to the published version of the manuscript
Download citation
DOI: https://doi.org/10.1038/s41598-022-25812-z
The prosecutors attached to the Bucharest Tribunal have received a notification regarding the suspicious deaths of patients admitted to the ICU ward of Saint Pantelimon Hospital
The hospital’s management confirmed to Antena3 that the prosecutors have received a notification and stated that they will also initiate their own investigation to find out exactly what happened
the Ministry of Health announced that it is sending the Control Body to Saint Pantelimon Hospital after a nurse reported that 20 patients had died due to improper administration of a medication
the director of care accuses that he is being prevented from carrying out his activities
"Following the notifications received from the director of care at the Saint Pantelimon Emergency Hospital regarding the hindrance of exercising his duties within the hospital
the Minister of Health has decided to send the Control Body to verify the reported aspects," the Ministry of Health stated in a press release on Thursday
The hospital's manager was informed in writing by the director of care that there is information from an unnamed nurse that between April 4-7
20 patients in the ICU ward died due to incorrect administration of a medication
"The hospital's management has set up a committee composed of doctors from other departments to verify the reported aspects
the Ministry of Health's Control Body will also get involved in verifying these serious accusations related to patient safety
Since it involves medical professional activity
the support of the College of Physicians of Bucharest has been requested
will be forwarded to other competent institutions," the Ministry of Health further conveyed
Initially, information about the deaths at Saint Pantelimon Hospital was published by cetateanul.net
which announced that a report will be submitted to the Bucharest Prosecutor's Office
doctors in the Intensive Care Unit (ICU) are allegedly killing critically ill patients
doctors are deliberately reducing the prescribed dose of noradrenaline
a substance that is crucial for keeping patients alive
Sources from the hospital informed cetateanul.net that
stated on Antena3 that he has never encountered such accusations throughout his medical career
"There have been other notifications regarding the hospital's activities during this week
I have sent the Control Body following these notifications
This issue with a wave of deaths and so on
these are things that need to be ascertained
the professional competencies of the medical staff
so I cannot make any statements regarding this subject
I await the results from my colleagues at the Control Body and then we will act accordingly
because then there will be another type of investigation
alongside the administrative one we are conducting
There have been no complaints from patients
only complaints from some of the employees there
These are complaints that need to be verified
I prefer not to comment until I verify them
I have not encountered these kinds of accusations in my medical career so far," stated the Minister of Health
Metrics details
Crossbar networks are a cornerstone of network architectures
capable of operating both as standalone interconnections or as integral switching components in complex
The main advantages of crossbar networks are their non-blocking operation and unparalleled minimal latency
With the advent of large scale quantum networks
crossbars might be an important asset towards the Quantum Internet
This study proposes a solution for the problem of distributing entanglement within crossbar quantum networks
Entangled particles are a consumable resource in quantum networks
and are being used by most quantum protocols
By ensuring that nodes within quantum networks are being supplied with entanglement
the reliability and efficiency of the network is maintained
scalable framework that can be used to achieve optimal entanglement distribution within crossbar quantum networks
this study offers a theoretical achievement which can be also used for enhancing quantum network performance
An algorithm for selecting an optimal entanglement distribution configuration is proposed and fully tested on realistic possible configurations
This necessity poses a significant challenge: while e-pairs must be shielded from external influences to maintain high fidelity for transmissions over long distances
they also require precise manipulation and measurement
The Quantum Internet is envisioned as a global network that interconnects heterogeneous quantum networks
but also with the preservation and manipulation of quantum states
Their development and optimization thus stand as a cornerstone in realizing the full potential of quantum communications and computing
Crossbar interconnection networks in particular hold significant potential due to their unique properties
like their ability to create direct and dynamic connections between inputs and outputs
which can greatly enhance the efficiency of information transmission
This is crucial in quantum computing environments where the rapid and reliable exchange of quantum states is essential
simulation results and interpretations are presented
The paper ends with conclusions regarding the optimality and scalability of the presented entanglement distribution algorithm
a cornerstone of performance is the seamless and efficient transfer of data between communicating parties
The concept of interconnection networks represents the backbone of data transfer
Interconnection networks (interconnects) are complex topological structures that facilitate data transmission between multiple components
an interconnection network is a structured arrangement of communication links and switches
designed to ensure efficient data exchange
depending on the chosen interconnection architecture
and network switching fabrics of the Internet
Such topologies include Linear Arrays and Rings
with network components connected in a straight line or loop
These can offer a simple way to route data
Meshes and Toruses expand upon these topologies
Hypercube topologies are a binary n-dimensional construct
Crossbar networks offer direct connections between every input and output
and stand out for their non-blocking nature
this advantage comes with the cost of being resource-intensive in terms of implementation
(a) represents a crossbar network topology
In (b) an example of how routing is performed between inputs and outputs within a crossbar
It should be noted that the number of inputs does not necessarily need to match the number of outputs
Traffic routing essentially determines how network resources (links and switches) are assigned for message transmissions. Traffic routing through a crossbar network is fairly straightforward. As we can see in Fig. 1b
the traffic needs to flow along the row of the input until the row intersects with the column of the output
the corresponding switch will route the traffic along the column
This scheme ensures non-blocking communication
regardless of the chosen permutation of inputs and outputs
The realm of quantum computing introduces many complex and intriguing concepts
Envisioning a quantum analog of classical crossbar interconnection networks
we can reach a grid-like architecture of intermediary nodes
the aim of such an interconnection network is not to transfer classical information through packets
but rather to transfer quantum information through physical particles
polarization states of photons can be easily prepared
manipulated and measured using commercially available optical elements
This makes it relatively straightforward to perform quantum operations on polarization-encoded qubits
we need to envision systems where the same photon which left one of the communicating parties is the same photon received by the other party
This is due to the fact that the atmosphere exhibits fluctuations of its refractive index
FSO communication is affected by background light (sunlight or artificial sources)
as these introduce noise in the quantum state
While error correction procedures have been developed for quantum communications
typically these require a minimal state of coherence to work
While optical fiber exhibits effects such as birefringeance or non-linear effects
these are generally more predictable and have a lesser effect compared to the challenges of FSO transmissions
An advantage of FSO is that transmissions can be made between a stationary and a moving target
Satellite-based quantum communication has achieved significant milestones
with qubits being transmitted between Beijing and Vienna
This is possible do to the fact that the drawbacks associated to terrestrial FSO transmissions - scattering
are mostly negated in transmissions above the atmosphere
as these were caused by interactions with air molecules
There has been a significant scientific focus in the area of satellite-based quantum networks as a result of this fact
It is of note that entanglement purification typically requires a minimal fidelity in order to function
and works best with e-pairs that already have a high fidelity
particularly in their ability to execute Bell State Measurements
This foundational operation is critical for quantum entanglement distribution networks
and is the minimum requirement of functionality of the intermediary nodes in the hereby presented scheme
Incorporating fully-fledged quantum repeaters with entanglement purification capabilities into the system architecture would theoretically enhance the entanglement fidelity across all stages of quantum state distribution
therefore increasing the terminal entanglement fidelity between network nodes
The possible functions of the Quantum Internet
all have in common the need for entangled particles
These entangled particles are essentials to protocols such as quantum teleportation and quantum key distribution
as they effectively act as a medium of information transmission that is secured by physical laws
Alice begins with a qubit in the \(|\psi>\) state
and Alice performing a partial measurement
Bob can retrieve the exact state that Alice began with
The protocol proposed harnesses the advantages of satellite platforms to mitigate the signal loss inherent in terrestrial fiber networks
which has been a major bottleneck for long-distance quantum entanglement
By generating entangled photons on a satellite and distributing them to ground stations
the researchers have circumvented the limitations posed by Earth’s atmosphere and curvature
The high-fidelity entanglement achieved across distances of up to 2400 km is particularly notable
demonstrating that quantum correlations can be maintained over scales far exceeding traditional fiber-based systems
The approach benefited from cutting-edge technologies
including narrow-beam divergence to reduce photon dispersion and dynamic polarization compensation to counteract the alterations caused by the satellite’s motion and atmospheric interference
a foundational process in the emerging Quantum Internet
The entanglement distribution challenge is approached by formulating it as a Markov Decision Process
which enables the modeling of decision-making in quantum network nodes
The model distinguishes between fixed parameters that depend on the underlying quantum network technology
such as the time horizon for distribution and the probability of successful entangled pair transmission
and design parameters that can be manipulated to achieve desired outcomes
This reward function is pivotal in guiding the decision-making process
ensuring larger distributed cluster sizes and shorter distribution times
The Markov Decision Process-based model is concluded to be a valuable tool for quantum network designers
providing a method to adjust and control the entanglement distribution process to meet specific performance benchmarks
This work not only aids in the practical engineering of quantum networks but also contributes to the foundational infrastructure necessary for realizing the Quantum Internet
with implications for secure communications and distributed quantum computing
Another recent work focused on optimal entanglement distribution over star-shaped topologies53
two primary distribution methodologies have been introduced: symmetrical and asymmetrical approaches
These relate to the way intermediary nodes are allocated for intersecting routes
In order to perform the entanglement distribution within a single transfer cycle
each route can either do it’s measurements on odd-numbered nodes
and entangled pair generation on even-numbered
This choice influences the success probability of establishing entanglement between the two terminal nodes
The findings of this study suggest that the choice of entanglement distribution strategy should be adaptive
depending upon the network’s transmission success probabilities
networks with less reliable transmissions should use the symmetrical approach
where intersecting routes contend over the same intersecting node
networks with highly reliable quantum operations should use an asymmetrical approach
which provides simultaneous resolution to multiple entanglement requests
In order to describe how we can distribute entanglement through a crossbar quantum network
we first need to define the purpose of the inner nodes of the crossbar
these should be able to perform basic qubit manipulation
they should be able to perform Bell State Measurements (BSM)
and be able to generate new entangled pairs
we can effectively make two separate parties share an entangled pair without actually having to physically transport an entangled particle all the way from one party to the other
An ideal application of entanglement swapping would be if two parties supply an entangled particle to a node that is situated at half the distance between the two of them
The node would then perform a BSM on the two particles thus shifting the entanglement to the two particles with whom they were each previously entangled to
The advantage of such a distribution scheme relies in preserving entanglement fidelity
As the quantum state coherence is affected by environmental factors
so too is the entanglement fidelity of entangled particle pairs
by exposing the state a shorter time to external factors
we preserve more of the initial entanglement fidelity
In the example application for entanglement swapping
we are effectively halving the distance the particles need to travel
and fidelity loss scales exponentially with the distance traveled
we not only end up with a higher fidelity entangled pair in the end
but we are doing so two times faster than by transporting the particle between the two parties (for which we will use a common naming convention - Alice and Bob)
An alternative solution to efficiently transmit an entangled pair to Alice and Bob would be to have a node midway between them
This midway node would generate an entangled pair
Since the act of measurement itself is imperfect
it is natural that we want to minimize such operations in our process to distribute entanglement
Compared to the previous distribution scheme
this one does not involve any measurements
only the entangled pair generation and two transmissions
each with half the distance between Alice and Bob
this distribution scheme where we are not performing an entanglement swap is preferable
and in the algorithm proposed in the following sections
we do not consider the usage of a quantum memory
The hereby proposed scheme is a solution where entanglement is generated and transmitted in the least amount of time possible
such that quantum state coherency is exposed to as few environmental factors as possible
classical crossbar networks are employed in small scales
where the transmission time between nodes is negligible
we wish to employ a crossbar quantum network over large distances
we would need to account for this transmission time
and therefore use quantum memories to store entangled particles for the Bell State Measurements
Regarding the capabilities of the quantum memories used
the coherence time of these quantum memories should be expected to be minimally equivalent to the duration needed for a photon to traverse the network’s longest link
If we were to consider longer coherence times for the quantum memories
such that entanglement could be preserved between the operation cycles of the crossbar
there may be more optimal solutions for the distribution of the entanglement
if the capacity of the quantum memories allows for more than one qubit to be stored
this may allow more sophisticated distribution schemes
We consider these scenarios to be open problems in the realm of entanglement distribution
Regarding the fidelity of the quantum memories
ideally these should be as high as possible
we acknowledge that quantum state coherence degradation might occur over time in quantum memories
and a trade-off might occur when choosing to serve a stored entangled qubit instead of generating a new one
This aspect should be taken into account in any further scenario that leverages quantum memories
The previously mentioned scenarios only involve three nodes: Alice
and a midway node which either performs a BSM
Transmissions of entanglement are limited by the distance that the photon can travel
multiple nodes might need to be placed between them in order to facilitate transmission of quantum information
we need to adapt the aforementioned methods to the situation where there are multiple intermediary nodes between Alice and Bob
Four efficient entanglement distribution possibilities along a chain topology
and we use an odd distribution scheme: nodes 3 and 5 perform the BSMs
the process of odd distribution is depicted along an even number of nodes
with nodes 3 and 5 performing the BSMs as well
the less efficient even distribution is used along an odd number of nodes
the even distribution is used along an even number of nodes
with only nodes 2 and 4 performing the BSMs
The benefits of such an alternating distribution scheme are manifold
the particles have to travel at most the distance of the longest link in the chain
This would lead to a lower fidelity loss of the entanglement
Another result of this fact is that the entire operation would take as much time as it takes for a photon to travel the distance of the longest link
This would also positively affect the final fidelity of the entangled pair shared by Alice and Bob
we are fully utilizing the qubit-manipulation capacity of the network
in the cases where the number of intermediary nodes is even
there is indeed no difference in the number of BSM performed in total
it is preferable to perform an odd distribution
as it would imply one less BSM than the even distribution
This would increase the success rate of the distribution
we will explore how these concepts can be applied for a crossbar quantum network
and how to find the optimal distribution scheme for any particular input–output configuration of the crossbar
The principles of even and odd distributions can be extended and applied within the context of a crossbar architecture as well
we will consider an \(N \times N\)-sized crossbar
we need to define an operational cycle of the crossbar quantum network
a cycle is represented by the basic unit of time during which information transfer operations are executed
we can define a tuple of input–output pairs
that describe the way quantum information flows through the crossbar during that cycle
(a) is an example entanglement distribution on a \(4 \times 4\) crossbar where we use the following boolean values to describe the distributions: [false
there is an example of a distribution where the used distribution scheme does not work
they would end up using the same node to perform the Bell State Measurement
This would not lead to the desired entanglement distribution
As we can see in Fig. 4b
the choice of whether or not to perform an odd distribution—which would be preferable due to the lower number of BSMs that it would imply
If we assign an odd distribution for every pair
we end up in a state where a single node would need to simultaneously perform a BSM for two separate incoming pairs of particles
as it would not swap the entanglement in the way that was intended
we need to find a way to assign the routes an even or odd distribution
in a way such that a node only performs a BSM for one pair at a time
As there are only two possibilities for each input–output pair
it might seem feasible to try out all the possible combinations for fairly small crossbar sizes
Such an approach would be faced a problem - how to determine if a combination is correct
we need a way to determine whether or not two input–output pairs intersect
what combinations does their intersection allow
In order to determine whether or not two input–output pairs intersect
we need only to consider the tuple that describes the flow
we will consider all other pairs that have the input index larger than the current one
By looking only at the routes that have their input index higher
we are essentially looking at routes that start from a lower position in the crossbar
Two routes can intersect if the route that starts lower has its’ destination further right than the one that starts higher
this means that if there are any pairs that have their input index higher than the one we are currently assessing
In order to efficiently determine which routes intersect
we may sort the tuple by their input index
we will look at all the next pairs and perform this check
This intersection check would still have an algorithmic complexity of \({\mathcal {O}}(n^2)\)
larger than the complexity for sorting the tuple
Note that we only performing the lookup for larger indices
as it is sufficient to detect the intersection once
we would detect intersections two times: once from the route that starts above
In (a) it can be observed that the number of nodes
minus the destination of the uppermost route
due to the fact that we consider the input node as part of the topology as well
the uppermost route has to travel the difference between both input nodes
The node where the path switches should not be counted twice
that is why we subtract 1 from that part of the equation
Based on the parities for the intersection node
we can impose some constraints upon the boolean values assigned for each route
In order to formally define these constraints
we will consider the following convention: the boolean variable i will be uniquely assigned to route (i
and will determine whether it will use an even or odd distribution
There are 4 possibilities regarding the parities for the intersection node
this means that they cannot both use an odd distribution at the same time
This constraint translates to \((i \vee k)\)
the first route cannot be odd while the second is even
This constraint can be written as \((\lnot i \vee k)\)
meaning that the constraint is \((\lnot i \vee \lnot k)\)
These constraints need to be satisfied for all routes simultaneously - conjoined with an \(\wedge \)
we have a formula in the conjunctive normal form (CNF)
Having an array of booleans and a CNF formula means that this problem falls in the category of 2-satisfiability (2SAT) problems56
it is not enough to know if an input–output pair tuple is satisfiable
we also need to know the boolean configuration which satisfies the constraints we have imposed
we want optimality in terms of the lowest numbers of Bell State Measurements performed
we want as many odd distributions as possible
This means that we want a boolean configuration which satisfies the constraints
the problem which we want to solve can be expressed as follows
where all conditions are imposed by the way the routes intersect
Optimal distribution configuration over the crossbar
With an input–output configuration of [(1
it is impossible to find a configuration that wouldn’t result in a double measurement in at least one node
if routes 2 through 4 use an even distribution
the path for route 1 would have 3 consecutive nodes where BSMs are performed by the other routes
route 4 has 2 consecutive nodes which are used for BSM by routes 2 and 3
we have simulated all the possible input–output configurations for crossbars up to an \(10 \times 10\) size (the simulations were performed on a machine equipped with an AMD Threadripper 5975WX
simulating crossbars of larger size would have been an increasingly difficult task
how there is no configuration possible where we can avoid having to measure multiple pairs in the same node
The rate of unsatisfiable configurations in relation to the size of the crossbar
The \(4 \times 4\) crossbar has a single unsatisfiable configuration out of the 23 total possible
The rate of unsatisfiability greatly increases afterwards
reaching almost 50% for a \(7 \times 7\) crossbar
even though a crossbar quantum interconnection constructed in the manner described would indeed transfer entanglement within the minimal and deterministic latency
it cannot fulfill the basic purpose of the classical crossbar interconnection
that is to offer a channel from every input to every output
to provide non-blocking communication with low
using crossbars up to size \(3 \times 3\) would be feasible
as there are no configurations where those have concurrency over an intersection node
Logarithmic plot of the number of intermediary nodes placed within \(2 \times 2\)-sized crossbars within a Beneš network
It can be observed that for relatively low number of inputs/outputs (approx
a full crossbar would have required less intermediary nodes
this would have come at the cost of the impossibility of performing efficient entanglement distribution for certain input–output configurations
as the Beneš network is a special case of the Clos network
where the crossbars have a \(2 \times 2\) size
we may use crossbars of size \(2 \times 3\)
to construct a non-blocking multi-stage interconnection network
This paper introduces an approach that addresses a problem not been previously investigated
efficiently distributing entanglement through a crossbar quantum interconnection network
Efficient distribution of entangled particles plays a pivotal role in enhancing quantum communication
where entanglement is a building block for secure data transfer
efficient distribution of entanglement is essential for scaling up systems and maintaining coherence across qubits
thereby improving computational capabilities
We have proposed two different distribution strategies for any route within the crossbar: even distribution and odd distribution
These distribution strategies ensure minimal latency for the entanglement distribution operation
though the odd distribution has a greater success rate
due to one less Bell State Measurement being performed
Choosing the optimal configuration for an operation cycle of the crossbar
is therefore a problem of optimizing the number of odd distributions performed
while satisfying the constraints being placed between individual routes
intermediary nodes may perform only one BSM at a time
It should be noted that this way of distributing entanglement is not the only one possible
as we are imposing a harsh condition upon the qubits that we are transmitting - they do not remain coherent for more than a crossbar cycle
We are imposing this without losing generality
as operating with coherence times lower than this would be impossible
as they would not even survive the transmission within the links of the crossbar
protocols where the qubits can be stored within the nodes for multiple cycles can be an interesting research direction
We have analyzed the capabilities of the distribution strategies over the crossbar quantum network
computing the optimal distribution strategies for all possible scenarios for crossbars up to size \(10 \times 10\)
We have found that there are input–output configurations where it is not possible to distribute entanglement in a non-blocking fashion using the proposed distribution strategies
if the crossbar has a size greater than \(3 \times 3\)
multistage network using crossbars of smaller sizes
we propose an analysis of optimality in terms of expected time of completion of the entanglement distribution process
Another proposed research direction is entanglement distribution in blocking interconnection networks
Another proposed analysis involves determining the best distribution strategy for qubits that can be stored at intermediary nodes for an unspecified duration in a quantum memory
Yin, J. et al. Bounding the speed of spooky action at a distance. arXiv:1303.0614 (2013)
Simple proof of security of the BB84 quantum key distribution protocol
Quantum teleportation based on non-maximally entangled graph states
Nielsen, M. A. The entanglement fidelity and quantum error correction. arXiv:quant-ph/9606012 (1996)
Overcoming noise in entanglement distribution
Topological Structure and Analysis of Interconnection Networks Vol
Development of quantum interconnects (quics) for next-generation information technologies
Optical interconnection networks in data centers: Recent trends and future challenges
Mathematical Theory of Connecting Networks and Telephone Traffic (Academic Press
Unconditional security of quantum key distribution over arbitrarily long distances
A study of non-blocking switching networks
Scalable crossbar network: A non-blocking interconnection network for large-scale systems
Full polarization control for fiber optical quantum communication systems using polarization encoding
Twin-field quantum key distribution over 830-km fibre
Pirandola, S. Capacities of repeater-assisted quantum communications. arXiv:1601.00966 (2016)
Path selection for quantum repeater networks
Quantum repeaters based on entanglement purification
Efficient quantum repeaters without entanglement purification
In International Conference on Quantum Information QMI14 (Optica Publishing Group
Quantum secure direct communication with quantum memory
Optimizing high-efficiency quantum memory with quantum machine learning for near-term quantum devices
Satellite-based entanglement distribution over 1200 kilometers
Entanglement distribution in the quantum internet: An optimal decision problem formulation
Optimal quantum network decongestion strategies
“Eevent-ready-detectors” bell experiment via entanglement swapping
The decision problem for a class of first-order formulas in which all disjunctions are binary
Improved approximation algorithms for max sat
Download references
Luca Perju Verzotti & Pantelimon George Popescu
and L.P.V.; writing—original draft preparation: B.C.C.
and P.G.P.; writing—review and editing: B.C.C.
Download citation
DOI: https://doi.org/10.1038/s41598-024-62274-x
Sign up for the Nature Briefing newsletter — what matters in science
Representatives of the Physicians’ College presented the results of the investigation at St
there was no suspicion of any deviation from protocols or that anyone had deliberately taken a patient’s life
The President of the Disciplinary Committee of the Bucharest College of Physicians
stated in a press conference that in all the incriminated cases
we first followed the discussion with the doctors on each file because I must tell you that in some cases
from two up to six doctors from the same department
This would have implied that all six doctors had a behavior that was not appropriate medically or professionally," said Liana Pleş
"The Committee analyzed each of the 17 death cases individually and interviewed 23 doctors
namely all the doctors from the ICU department
we retained those who were present and related to the respective cases
mostly transfers from other hospital departments
some after several months of hospitalization
Some came already with resuscitated or non-resuscitated cardiac arrest from outside the hospital
there was also a transfer from another hospital
a very serious case that deteriorated on the same day," explained the President of the Disciplinary Committee
The protocols of the Romanian Society of Anesthesia and Intensive Care were followed
the entire course of each patient in the hospital
(...) We checked if there were protocols of the Romanian Society of Anesthesia and Intensive Care
which are the ones that all doctors must respect in their professional activity
and also we checked the entries in the observation sheet point by point
respectively if the doses administered were in line with the indications
if they were adjusted or adapted to the clinical situation of each patient
there was no suspicion that there was any deviation from these protocols or that someone intentionally
especially since in some cases there are entries from several doctors on the same day
had committed a deliberate act to suppress or reduce for criminal purposes," added Liana Pleş
Several investigations have been initiated
following accusations regarding the death of several patients in just a few days in the ICU department of the Emergency Clinical Hospital "St
due to the improper administration of a medication
The Ministry of Health's Control Body has issued preliminary conclusions
stating that the verifications focused only on the administrative activity of the unit
"The complaints are based on a faulty communication," stated the Ministry of Health
The Prosecutor's Office attached to the Bucharest Tribunal also initiated a criminal investigation into the crime of homicide
Three employees of the medical unit were interviewed
Gabriel Pantelimon (pictured) was appointed Country General Manager of Xerox Romania and the Moldova Republic
Formerly sales and marketing director in Xerox Central Eastern Europe
Pantelimon will be replacing Petr Sichrovsky starting with November 1
He will be in charge with coordinating marketing and sales activities
global services and customer services operations for Xerox Romania and Moldova Republic
“I will continue the XEROX strategy focused on services and solutions for the management of documents and together with the team I wish we will achieve performance, irrespective of the economic conditions,” he said.
The following year he was appointed global accounts manager in Xerox Central Eastern Europe
Israel and Turkey while in 2009 he became sales and marketing director in Xerox Central Eastern Europe
being in charge with achieving significant sales and boosting profit in a challenging recession period
Rosenblum moderating a panel during the EHSI Mid-term Meeting (from left to right: Dr
At the end of November, I had the pleasure of co-hosting a mid-term meeting for the Environments and Health Signature Initiative (EHSI)
in collaboration with the CIHR Institutes of Population and Public Health
Circulatory and Respiratory Health and Human Development
INMD has participated in the EHSI by leading the etiological research component on environment-gene interactions. The aim of this component is to advance our understanding of how environment-gene interactions affect disease patterns and human health across the life course. I would encourage you to read more about this funded research on the CIHR website
Each meeting participant provided a very short overview of their research as an introduction to their project and research team
Keynote presentations were provided by Dr
National Institute of Environmental Health Sciences (NIEHS)
Bernard Robaire (McGill Univ.) who provided high-level perspectives on environmental health research
Plenary sessions that followed included a focus on data
and how the various EHSI-funded researchers are handling issues such as the inter-operability and data sharing
There was also an interesting panel on knowledge translation for maximizing impact that included perspectives on how research impacts regulatory processes and urban planning policies
and how two of the National Collaborating Centres funded by the Public Health Agency of Canada (PHAC) are engaging with communities
to address environmental health research issues
I wish to thank the researchers who participated in this meeting
and wish them continued success with their programs of research
and all the best for a healthy and productive 2019
FMCG and construction materials manufacturer Henkel has invested RON 3.4 million (approximately EUR 770,000) in increasing the energy efficiency of its factory in Pantelimon
RON 0.9 million (approximately EUR 200,000) are EU money
The project was implemented between March 2012 and this February and it consisted in a new sand drying technology
the factory’s energy consumption for the sand drying process should decrease by at least 10 percent
The project is part of a global strategy and similar upgrades will be implemented in the manufacturer’s other two local factories – the one in Campia Turzii and the one in Roznov which will be opened this year
Henkel construction materials are sold under the Ceresit brand.
the new factory should have become operational in 2012 but its opening was delayed for the first half of 2013
It will have a production capacity of between 180,000 and 200,000 tons per year and it will cover mainly the Northern part of Romania as well as exports to the Republic of Moldova
The new production facility will employ around 70 people
Henkel Romania was set up in 1994 as a subsidiary of Henkel Central Eastern Europe, and presently employs over 500 people.
the national leader in the retail of construction materials and interior design
opens on September 7th the Pantelimon store
the 6th in Bucharest and the 49th nationwide
and its implementation implied a budget of about EUR 15 million
Built on an area of more than 14,500 sqm
Dedeman’s newest investment also features a generous parking consisting of 504 spaces
In order to respond as quickly and fully as possible to the requests from the customers of the new store, a team of 216 employees was carefully recruited, trained and specialized in the other stores in Bucharest so as to reach the level of expertise Dedeman customer.
”The opening of the Pantelimon store is another step in our strategy to efficiently cover the capital with shops close to our customers and accessible from any part of the city and its surroundings
We are confident that customer proximity and low response times can keep us competitive in a market marked by changes and challenges,” said Dragos Paval
the company put its money in the stock exchange and
in central western Bucharest for EUR 200 million
CA Immo exits non-core market Serbia with the sale of the 19,600 sqm office building Sava Business Center in Belgrade
Both the sales price and the buyer are subject to confidentiality
As the PBSA sector finally takes off in Poland
it is now increasingly attracting international operators and investors
Eurobuild CEE spoke to Xior's investment manager
about why it has such confidence in the Polish market
Residential developer Develia has signed a preliminary agreement to acquire all the shares in Bouygues Immobilier Polska
the Polish subsidiary of Bouygues Immobilier
ESA logistika has leased 15,000 sqm in Prologis Park Piotrków
GLP has completed the development of its Wrocław V Logistics Centre and has received a BREEAM rating of Outstanding
Panattoni has secured EUR 40 mln in financing from BNP Paribas for the development of Panattoni Park Sosnowiec IV
Newgate Investment (NGI) and Redkom Development are developing a large retail park in Bydgoszcz
Deutsche Hypo – NORD/LB Real Estate Finance has provided a five-year green loan to Olivia Seven for the refinancing of the Olivia Prime A office building in Gdańsk-Oliwa
communications and security company Motorola Solutions has signed a five-year lease renewal
18,000 sqm at the Green Office complex in Kraków’s Podgórze district
Falling interest rates and easing monetary policy across the eurozone and CEEi are boosting investor confidence in the region’s commercial real estate market
reveals Colliers in its ‘Beyond Real Estate | Economy’ report
Panattoni is to build the Panattoni Park Mainz Süd in Erbes-Büdesheim bei Alzey
Axi Immo has presented its latest report “Warsaw Office Market – Q1 2025
The market opened in 2025 on a steady footing
with a notable increase in leasing activity and a modest decline in vacancy
landlords continue to focus on upgrading existing assets and prioritizing quality over quantity
Convenience store chain Żabka has officially opened a new logistics centre in Kąty Wrocławskie
The first stage of the development will serve 1,500 stores in the Wrocław area
Romanian Post has leased over 5,000 sqm of logistics space in CTPark Bucharest to serve as its temporary regional courier and logistics hub for Bucharest
JLL has announced the sale and leaseback of two properties by a manufacturing company in a deal worth over PLN 1 bln
Warehouse developer CTP is adding 2,000 sqm to its Clubco coworking development in Brno
pbb Deutsche Pfandbriefbank has extended an investment facility to PineBridge Benson Elliot for the Diuna Office Park in Warsaw
The hotel market in Bucharest continued its recovery in 2024
while the ADR has finally surpassed the milestone of EUR 100
Torus has announced its All.inn students’ residence concept that is soon to appear on ul
BIG Poland has acquired the Multishop Suwałki retail park comprising 13,000 sqm of retail space
The company now owns nine fully commercialized retail parks in Poland
Slate Asset Management has sold three OBI retail stores to the Lindner Group from Germany
Cushman & Wakefield has conducted a survey
the findings of which are presented in the report From Shopping to Experiences: A Customer’s View on Shopping Centres and Retail Parks
Cushman & Wakefield notes that despite evolving shopping trends
both retail formats continue to hold strong appeal
Multi Poland has taken on the management of the Galeria Przymorze shopping centre in Gdańsk
The store offers lifestyle and sporting clothing and is to open this spring
According to the "Quo Vadis E-commerce" report released by Cushman & Wakefield
the online commerce continues to be a growth driver for the industrial & logistics real estate sector
generating significant opportunities for developers and investors
the investor behind the Projekt Góraszka shopping and entertainment complex in Wiązowna on Warsaw’s eastern outskirts
has obtained a building permit for a mixed-use development
Poznan-based company Scallier is opening another facility under the Funshop Park brand in Romania
According to the latest report “At a Glance: Modern Retail Market in Poland
Q4 2024” from BNP Paribas Real Estate Poland
Poland’s retail market experienced record growth in 2024
Cushman &Wakefield has summarised the situation on the Polish retail market
Over half a mln sqm of new retail space came on stream last year
marking the highest new supply level in Poland since 2015
This robust development activity occurred amid rising demand from new retailers and improving consumer sentiment which boosted retail sales
A new retail park with a total area of 24,000 sqm is set to be developed in Otwock under the name Świderek
The investment will be led by Redkom Development
Empik has opened a flagship store in the revitalised former Cepelia pavilion in the centre of Warsaw
the modernist building has regained its former glory and once again impresses with its original appearance and modern interior
Trei Real Estate Poland has opened its 40th Vendo Park
The investment was created in Wrocław and has 5,000 sqm
Vendo Park Wrocław is the first facility under this banner in the capital of Lower Silesia
The retail park was built on a plot of approx
An 800 sqm Biedronka grocery store is to open on the ground floor of the Moje Bielany residential complex
which is being developed by CeMat A/S at ul
Wólczyńska 121 in Warsaw’s Bielany district
Spring has very much sprung and everywhere is bathed in the first warm sunshine of the year
I have in the back of my mind the terrifying fo ..
The Polish warehouse market has finally stabilised after the post-pandemic boom
but new challenges and opportunities are on the horizon for the sector
UBM Development has been given the go-ahead for the first wooden office building in Poland: Timber Park in Poleczki Business Park in Warsaw
The office market in Warsaw is currently experiencing a period of stability in terms of supply and take-up
Recent data on overall tenant activity indicates that clients in the cap ..
Receive all the latest information from the world of real estate by e-mail
the construction of the Aura residential building
designed by Robert Konieczny's office KWK Promes
According to a report by research company Spectis “Construction companies in Poland 2025-2030”
the total revenues of the 300 leading construction gro ..
The Globalworth Foundation has provided the authorities in Bucharest with office space for a Covid vaccination centre
Panattoni BTS and Commercecon together support the establishment of the second Centaurus Foundation centre in Poland to help horses and other animals
intends to focus on operations in other reg ..
Six class A office buildings in the PRO Portfolio
which is jointly owned by PineBridge Benson Elliot and Sharow Capital have been granted BREEAM In-U ..
Who won this year's 14th edition of the Eurobuild Awards
The jury and guests gathered at the Double Tree by Hilton hotel in Warsaw chose this year's ..
Enjoy the last set of recordings with comments straight from this year's MIPIM
we asked experts from our home country for their input
will take place on 9-10 April 2025 at the Norblin Factory Event Hall in W ..
we invite you to hot episode of the "Eye to eye" podcast
The UN Nansen Refugee Award award will go to Poland for the first time
According to the office of the UNHCR High Commissioner this year's regional wi ..
Czech developer CTP has been granted a EUR 200 mln loan from the European Investment Bank for the roll-out of its large-scale solar panel installation ..
while the ADR has finally surpassed the milestone ..
Jarosław Szanajca plans to resign from the position of president of the management board of Dom Development at the end of the year and join the superv ..
The Polish and Danish governments have entered preliminary discussions for the construction of a tunnel between Szczecin and Copenhagen underneath the ..
Viterra has moved into its new 1,500 sqm offices in Olivia Prime
part of the Olivia Centre business complex in Gdańsk
Panattoni has acquired two properties near Gothenburg
The brownfield sites will be replaced by a modern 43,000 sqm facility
Contemporary cities are grappling with the challenge of fostering dynamic growth while alleviating environmental pressures
Colliers has taken over the management of the Studio B office building located in the Warsaw Wola district
The property is owned by Stena Real Estate ..
The University of Warsaw has signed a contract with the general contractor for a project at ul
The new building will house the faculti ..
Velis Real Estate Tech is officially changing its name to Singu
adopting the title of its property management product
the construction of the Panattoni Park Unterfranken has officially started
The operator of the Bucharest subway network
the construction company building the 5th subway line between Drumul Taberei and Pantelimon
according to Transport Minister Lucian Sova
who resigned yesterday from his position but whose resignation has not been signed by president Klaus Iohannis
Lucian Sova said that Astaldi can block the activity of the subway at any time since it has won all the trials regarding the debt and it has a court order for the foreclosure of the company
“If they want to close the subway, they can, since they have a court decision. The government knows about the situation. I have been making efforts in the last three months to to pay this amount and have also tried to identify the guilty parties,” said Lucian Sova.
The Control Body of the Minister of Transport carried out checks at Metrorex aimed at observing the legal and contractual provisions of the design and execution contract for subway line 5 and its stations
Checks were conducted between 22-31.08.2018 and the audit revealed deficiencies in the implementation of the project
which led to delays in the performance of the contract but also to the additional costs for Metrorex
The report shows that the value of the contract was underestimated when the procurement procedure was launched
“As a result of the analysis of the way the public auction and the procedure for setting the contractual terms and the implementation of the contract were prepared and carried out, it was found that additional costs were incurred by the contracting authority in favor of the contractor amounting to more than RON 188 million,” show the press release.
The inspection body has notified the Anti-Fraud Department-DLAF for research and action
The death toll following the Colectiv club fire accident in Bucharest reached 32, while another 136 wounded are still hospitalized across several Bucharest hospitals, of whom 57 people are in critical condition.
One young man who is yet unidentified died today, taking the current death toll to 31, according to Mediafax newswire
The Romanian Healthcare minister appointed a commission that will be in charge with coordinating the activity of hospitals that are treating the wounded from the Colectiv fire
The team will assess the state of patients
or if the patients need to be transferred from one place to the other
The commission was at Bagdasar Arseni hospital, together with a team of French doctors who arrived in Bucharest on Sunday evening, and will then go to the Bucharest UniversitarEemergency Hospital, the Elias hospital, Floreasca emergency hospital, and the Grigore Alexandrescu children’s hospital.
Militari hospital announced on Monday that the state of three patients who are hospitalized at the Intensive Care has improved and they can be moved on the burns unit
Other five patients are still in serious conditions while one of them is still intubated
After the accident, some units in Bucharest’s Municipal hospital, such as the intensive care and plastic surgery units, were overcrowded.
who operated on patients at the Bagdasar Arseni hospital
will arrive at the Municipal hospital today to help the Romanian medical team
Twenty people injured in the fire were hospitalized at the Bucharest Universitar Emergency hospital
One of the victims was well enough to be sent home
Nine of the remaining 19 are still in critical condition
At the Floreasca hospital arrived 14 victims of the Colectiv fire
of whom 14 are still in very critical condition
all patients were sent to surgery rooms for surgical interventions
Civilians and institutions alike have started to rally their forces in support of the victims and families of the fire
See here an up-to-date list of the institutions that offered to help as well as a complete location of the places where those interested can donate blood.
Doctors have emphasized on various occasions that blood donations will be necessary not only in the few days following the accident but over the next few weeks
Wind developer Monsoon Group and Vestas will build a new wind farm in Constanta County
The project totals EUR 250 million and will create 250 new jobs
“Pantelimon wind park will be finalized in the summer of 2012
producing clean energy for 100,000 households
in the same time cutting yearly carbon emissions by 360,000 tons,” said Andrei Muntmark
Vestas will provide the 50 wind turbines necessary for this project. The company has already installed 119 turbines for several wind parks in Romania, with an installed capacity of 320 MW.
Monsson has developed 2,400 MW of wind installations
out of which 750 MW have been sold to Continental Wind Partners
The Group wants to increase its own electricity generation from 25 to 200 MW in the next 3 years
The company developed Fantanele-Cogealac wind park
one of the leaders in Romania’s construction industry
has inaugurated a new concrete plant in Mogosoaia
following an investment of 7.5 million RON
The group currently operates 3 facilities that produce concrete for engineering constructions
as well as an asphalt mix production station in Pantelimon
IBB Holding: “Through this new concrete station located in the north of Bucharest
we are in a favorable position to participate in tenders for infrastructure projects in this area and to establish strategic partnerships with real estate developers
we can ensure the quality of the materials used
providing faster and more efficient services
Our strategy is to offer integrated services with production
with responsibility towards the environment and future generations
tailored to each type of project we are involved in
The real need that Romania has in terms of investments in infrastructure
and the projects that have already started
give us a positive view on the development of our business in the medium and long term.”
The concrete plant in Mogosoaia is certified according to RENAR standards for producing concrete for engineering constructions
having a production capacity of 100 cubic meters per hour
The European Investment Bank (EIB) will provide an EUR 465 million loan to finance the design
construction and commissioning of Section II of the Bucharest Metro Line 5
The Bucharest Metro project involves the extension of Line 5 between Universitate and Pantelimon
the construction of the Pantelimon 2 depot
and the acquisition of 30 new trains for this line
which is expected to be in operation after March 2019
will increase the annual number of metro passengers by 34 million to almost 260 million
This metro line will link the Center to Eastern Bucharest
offering an alternative transportation route for 350.000 inhabitants
The construction of Section II will run in parallel with the building of Section I between Drumul Taberei and Universitate, which is also being co-financed by EIB with a loan of EUR 395 million signed two years ago.
The Premier League is the most-watched football league in the world
which is rated as one of Europe's top-5 leagues
is renowned for being the toughest in the world because of the relentless pace of games and the physicality involved
Despite its reputation for being a difficult league to play in, the Premier League has been graced by some of the best players in the sport
While players require pace to beat opposition players
the Premier League also has no dearth of players with imposing physical presence who are difficult to beat in the air and are especially huge assets in defence
let us have a look at the five tallest active players in the Premier League at the moment
28-year-old Nick Pope plies his trade for Burnley in the Premier League after joining the club in the summer of 2016 after several loan spells while he was with Charlton Athletic
The 6' 5" shot-stopper played all 38 games for Burnley in their last two campaigns in the competition in 2017-18 and 2019-20
keeping an impressive 27 clean sheets in 90 Premier League games for the club
Nick Pope has now kept more clean sheets (13) than any other goalkeeper in the Premier League this season.The race for the Golden Glove is on. 🧤 pic.twitter.com/eylzQDCoca
Pope's 15 Premier League clean sheets last season were only two behind that of Golden Glove winner Ederson as Burnley finished in the top half of the table
is currently playing his 11th season in the competition and seventh for Crystal Palace
the Welsh goalkeeper has made 110 Premier League appearances for the club
keeping 28 clean sheets during this period
Hennessey is presently behind first-choice custodian Vicente Guaita in the pecking order
4 - David de Gea made four saves with his feet for Manchester United in their recent game vs Spurs. No goalkeeper has made more saves with their feet in a Premier League game since 2008-09 & the last to make four was Wayne Hennessey for C.Palace vs Chelsea in April 2017. Boots. https://t.co/1y9e2JHC9s
Danish defender Jannik Vestergaard is one of the tallest active outfield players in the Premier League at the moment
After nine seasons in the German Bundesliga with three different clubs
the 6' 6" centre-back arrived in the Premier League in the summer of 2018 when he joined Southampton
Southampton have completed the signing of Danish defender Jannik Vestergaard from Borussia Monchengladbach More ➡️ https://t.co/E8bPhidL6f pic.twitter.com/jC40nUhPGZ
His tall stature makes him a difficult player to get past
Although Vestergaard is not renowned for his speed
he more than makes up for it with his impressive positional awareness and aerial prowess
The Danish defender has scored one goal in his 44 appearances in the Premier League with Southampton
who joined Premier League club Arsenal in the summer of 2014
was tipped to be the Gunners' future number one
the English custodian has yet to start a Premier League game for Arsenal and has instead been away in loan spells at Accrington Stanley
Macey has struggled to break into the Arsenal first team during his time at the club as he is behind first-choice Bernd Leno
It's a special day for our No 3️⃣3️⃣...Happy 25th birthday, Matt!🎈 pic.twitter.com/0aRnLo5Bsu
who plies his trade for Brighton & Hove Albion
is currently the tallest active player in the Premier League
who made 34 Premier League appearances for the Cottagers last season
helped his club escape relegation en route to a 15th-place finish
👇 #MondayMotivation from Dan Burn...“We’ve got an experienced group that’s been in this situation before and I’m backing us to get out of it.”#BHAFC 🔵⚪️ pic.twitter.com/NyQUDeiDi1
His imposing height helps him win a lot of aerial duels. Interestingly, Burn received a high-five from Manchester City's Sergio Aguero after effortlessly controlling a long ball aimed in the direction of the Argentine in a Premier League game last season
Your perspective matters!Start the conversation