Sandor Imre

Sandor Imre
Budapest University of Technology and Economics · Department of Networked Systems and Services

DSc.

About

436
Publications
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3,449
Citations

Publications

Publications (436)
Article
A deep dive into the quantum Internet's potential to transform and disrupt.
Article
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A scalable model for a distributed quantum computation is a challenging problem due to the complexity of the problem space provided by the diversity of possible quantum systems, from small-scale quantum devices to large-scale quantum computers. Here, we define a model of scalable distributed gate-model quantum computation in near-term quantum syste...
Article
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Accessing scarce resources in distributed systems where entities are not centrally coordinated, whether roebucks are fighting for a doe or WiFi users are competing for a common radio channel, is associated with moderate efficiency and proves to be a challenging problem. In this study, we present our hypothesis on shared entanglement and how such a...
Article
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
The cloud computing field suffers from the heavy processing caused by the exponentially increasing data traffic. Therefore, optimizing the network performance and achieving a better quality of service (QoS) became a central goal. In cloud computing, the problem of energy consumption of resource distribution management system (RDMS) is presented as...
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The quantum Internet enables networking based on the fundamentals of quantum mechanics. Here, methods and procedures of resource prioritization and resource balancing are defined for the quantum Internet. We define a model for resource consumption optimization in quantum repeaters, and a strongly-entangled network structure for resource balancing....
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Here, we define the entanglement concentration service for the quantum Internet. The aim of the entanglement concentration service is to provide reliable, high-quality entanglement for a dedicated set of strongly connected quantum nodes in the quantum Internet. The objectives of the service are to simultaneously maximize the entanglement throughput...
Article
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The entangled network structure of the quantum Internet formulates a high complexity routing space that is hard to explore. Scalable routing is a routing method that can determine an optimal routing at particular subnetwork conditions in the quantum Internet to perform a high-performance and low-complexity routing in the entangled structure. Here,...
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Quantum computers utilize the fundamentals of quantum mechanics to solve computational problems more efficiently than traditional computers. Gate-model quantum computers are fundamental to implement near-term quantum computer architectures and quantum devices. Here, a quantum algorithm is defined for the circuit depth reduction of gate-model quantu...
Preprint
Quantum memories are a fundamental of any global-scale quantum Internet, high-performance quantum networking and near-term quantum computers. A main problem of quantum memories is the low retrieval efficiency of the quantum systems from the quantum registers of the quantum memory. Here, we define a novel quantum memory called high-retrieval-efficie...
Preprint
Crucial problems of the quantum Internet are the derivation of stability properties of quantum repeaters and theory of entanglement rate maximization in an entangled network structure. The stability property of a quantum repeater entails that all incoming density matrices can be swapped with a target density matrix. The strong stability of a quantu...
Preprint
We define metrics and measures to characterize the ratio of accessible quantum entanglement for complex network failures in the quantum Internet. A complex network failure models a situation in the quantum Internet in which a set of quantum nodes and a set of entangled connections become unavailable. A complex failure can cover a quantum memory fai...
Article
Full-text available
Crucial problems of the quantum Internet are the derivation of stability properties of quantum repeaters and theory of entanglement rate maximization in an entangled network structure. The stability property of a quantum repeater entails that all incoming density matrices can be swapped with a target density matrix. The strong stability of a quantu...
Article
Full-text available
We define metrics and measures to characterize the ratio of accessible quantum entanglement for complex network failures in the quantum Internet. A complex network failure models a situation in the quantum Internet in which a set of quantum nodes and a set of entangled connections become unavailable. A complex failure can cover a quantum memory fai...
Article
Full-text available
Quantum memories are a fundamental of any global-scale quantum Internet, high-performance quantum networking and near-term quantum computers. A main problem of quantum memories is the low retrieval efficiency of the quantum systems from the quantum registers of the quantum memory. Here, we define a novel quantum memory called high-retrieval-efficie...
Article
Full-text available
In this letter, we derive the maximal achievable secret key rates for continuous‐variable quantum key distribution (CVQKD) over free‐space optical (FSO) quantum channels. We provide a channel decomposition for FSO‐CVQKD quantum channels and study the SNR (signal‐to‐noise ratio) characteristics. The analytical derivations focus particularly on the l...
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The subcarrier domain of multicarrier continuous-variable quantum key distribution (CVQKD) is defined. In a multicarrier CVQKD scheme, the information is granulated into Gaussian subcarrier CVs and the physical Gaussian link is divided into Gaussian sub-channels. The subcarrier domain injects physical attributes to the description of the subcarrier...
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A multicarrier continuous-variable quantum key distribution (CVQKD) protocol uses Gaussian subcarrier quantum continuous variables (CVs) for the transmission. Here, we define an iterative error-minimizing secret key adaption method for multicarrier CVQKD. The proposed method allows for the parties to reach a given target secret key rate with minimi...
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The theory of quantum gravity is aimed to fuse general relativity with quantum theory into a more fundamental framework. The space of quantum gravity provides both the non‐fixed causality of general relativity and the quantum uncertainty of quantum mechanics. In a quantum gravity scenario, the causal structure is indefinite and the processes are ca...
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The diversity space of multicarrier continuous‐variable quantum key distribution (CVQKD) is defined. The diversity space utilizes the resources that are injected into the transmission by the additional degrees of freedom of the multicarrier modulation. We prove that the exploitable extra degree of freedom in a multicarrier CVQKD scenario significan...
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Gate-based quantum computations represent an essential to realize near-term quantum computer architectures. A gate-model quantum neural network (QNN) is a QNN implemented on a gate-model quantum computer, realized via a set of unitaries with associated gate parameters. Here, we define a training optimization procedure for gate-model QNNs. By derivi...
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Full-text available
We define the statistical quadrature evolution (QE) method for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD protocol uses Gaussian subcarrier quantum continuous variables for information transmission. The QE scheme utilizes the theory of mathematical statistics and statistical information processing. The Q...
Preprint
Gate-model quantum computers can allow quantum computations in near-term implementations. The stabilization of an optimal quantum state of a quantum computer is a challenge, since it requires stable quantum evolutions via a precise calibration of the unitaries. Here, we propose a method for the stabilization of an optimal quantum state of a quantum...
Preprint
Gate-based quantum computations represent an essential to realize near-term quantum computer architectures. A gate-model quantum neural network (QNN) is a QNN implemented on a gate-model quantum computer, realized via a set of unitaries with associated gate parameters. Here, we define a training optimization procedure for gate-model QNNs. By derivi...
Article
Full-text available
Gate-model quantum computers can allow quantum computations in near-term implementations. The stabilization of an optimal quantum state of a quantum computer is a challenge, since it requires stable quantum evolutions via a precise calibration of the unitaries. Here, we propose a method for the stabilization of an optimal quantum state of a quantum...
Article
Full-text available
We define a nature-inspired model for entanglement optimization in the quantum Internet. The optimization model aims to maximize the entanglement fidelity and relative entropy of entanglement for the entangled connections of the entangled network structure of the quantum Internet. The cost functions are subject of a minimization defined to cover an...
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Full-text available
Gate-model quantum computers provide an experimentally implementable architecture for near-term quantum computations. To design a reduced quantum circuit that can simulate a high-complexity reference quantum circuit, an optimization should be taken on the number of input quantum states, on the unitary operations of the quantum circuit, and on the n...
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Quantum measurement is a fundamental cornerstone of experimental quantum computations. The main issues in current quantum measurement strategies are the high number of measurement rounds to determine a global optimal measurement output and the low success probability of finding a global optimal measurement output. Each measurement round requires pr...
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Connections between users of social networking services pose a significant privacy threat. Recently, several social network de-anonymization attacks have been proposed that can efficiently re-identify users at large scale, solely considering the graph structure. In this paper, we consider these privacy threats and analyze de-anonymization attacks a...
Article
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We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaus...
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Quantum entanglement is a crucial element of establishing the entangled network structure of the quantum Internet. Here we define a method to achieve controlled entanglement access in the quantum Internet. The proposed model defines different levels of entanglement accessibility for the users of the quantum network. The path cost is determined by a...
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Quantum entanglement is a building block of the entangled quantum networks of the quantum Internet. A fundamental problem of the quantum Internet is entanglement distribution. Since quantum entanglement will be fundamental to any future quantum networking scenarios, the distribution mechanism of quantum entanglement is a critical and emerging issue...
Article
A multicarrier continuous-variable quantum key distribution (CVQKD) protocol utilizes Gaussian subcarrier quantum continuous variables (CV) for information transmission. Here, we propose the Gaussian quadrature inference (GQI) method for multicarrier continuous-variable quantum key distribution. The GQI framework provides a minimal error estimate o...
Article
The power of quantum computing technologies is based on the fundamentals of quantum mechanics, such as quantum superposition, quantum entanglement, or the no-cloning theorem. Since these phenomena have no classical analogue, similar results cannot be achieved within the framework of traditional computing. The experimental insights of quantum comput...
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We define an adaptive routing method for the management of quantum memory failures in the quantum Internet. In the quantum Internet, the entangled quantum states are stored in the local quantum memories of the quantum nodes. A quantum memory failure in a particular quantum node can destroy several entangled connections in the entangled network. A q...
Conference Paper
Quantum measurement is a fundamental cornerstone of experimental quantum computations. We define a novel measurement for quantum computations called dense quantum measurement. The dense measurement aims at fixing the main drawbacks of standard quantum measurements.
Conference Paper
Quantum measurement is a fundamental cornerstone of quantum computers. We define a measurement optimization for gate-model quantum computers. The dense measurement aims at fixing the main drawbacks of measurement procedures in quantum computers.
Article
Full-text available
Quantum key distribution (QKD) protocols represent an important practical application of quantum information theory. QKD schemes enable legal parties to establish unconditionally secret communication by exploiting the fundamental attributes of quantum mechanics. Here we present an overview of QKD rotocols. We review the principles of QKD systems, t...
Article
Full-text available
In the quantum repeater networks of the quantum Internet, the varying stability of entangled quantum links makes dynamic topology adaption an emerging issue. Here we define an efficient topology adaption method for quantum repeater networks. The model assumes the random failures of entangled links and several parallel demands from legal users. The...
Preprint
In the quantum repeater networks of the quantum Internet, the varying stability of entangled quantum links makes dynamic topology adaption an emerging issue. Here we define an efficient topology adaption method for quantum repeater networks. The model assumes the random failures of entangled links and several parallel demands from legal users. The...
Article
p>One of the most important practical realizations of the fundamentals of quantum mechanics is continuous-variable quantum key distribution (CVQKD). Here we propose the adaptive multicarrier quadrature division–multiuser quadrature allocation (AMQD–MQA) multiple access technique for continuous-variable quantum key distribution. The MQA scheme is ba...
Article
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We define a multilayer optimization method for the quantum Internet. Multilayer optimization integrates separate procedures for the optimization of the quantum layer and the classical layer of the quantum Internet. The multilayer optimization procedure defines advanced techniques for the optimization of the layers. The optimization of the quantum l...
Article
Quantum repeater networks are a fundamental of any future quantum internet and long-distance quantum communications. The entangled quantum nodes can communicate through several different levels of entanglement, leading to a heterogeneous, multilevel network structure. The level of entanglement between the quantum nodes determines the hop distance a...
Article
Full-text available
A fundamental concept of the quantum Internet is quantum entanglement. In a quantum Internet scenario where the legal users of the network have different priority levels or where a differentiation of entanglement availability between the users is a necessity, an entanglement availability service is essential. Here we define the entanglement availab...
Conference Paper
p>A Poisson model for entanglement optimization in quantum repeater networks is defined in this paper. The optimization framework fuses the fundamental concepts of quantum Shannon theory with the theory of evolutionary algorithms and seismic wave propagations in nature. The optimization model aims to maximize the entanglement fidelity and relative...
Conference Paper
p>In quantum repeater networks, the varying stability of entangled quantum links makes dynamic topology resilience an emerging issue. Here we define an efficient topology adaption method for quantum repeater networks. The model assumes the random failures of entangled links and several parallel demands from legal users. The shortest path defines a...
Data
We propose an efficient logical layer-based reconciliation method for continuous-variable quantum key distribution (CVQKD) to extract binary information from correlated Gaussian variables. We demonstrate that by operating on the raw-data level, the noise of the quantum channel can be corrected in the low-dimensional (scalar) space and the reconcili...
Article
Full-text available
We propose an efficient logical layer-based reconciliation method for continuous-variable quantum key distribution (CVQKD) to extract binary information from correlated Gaussian variables. We demonstrate that by operating on the raw-data level, the noise of the quantum channel can be corrected in the low-dimensional (scalar) space, and the reconcil...
Article
Full-text available
Quantum information processing exploits the quantum nature of information. It offers fundamentally new solutions in the field of computer science and extends the possibilities to a level that cannot be imagined in classical communication systems. For quantum communication channels, many new capacity definitions were developed in comparison to class...
Conference Paper
The precise and stable working of quantum gates in quantum computers is essential for any quantum computations. We define a machine learning-based framework for the unsupervised control of entangled quantum gates in gate-model quantum computers.
Conference Paper
A fundamental concept of the quantum Internet is quantum entanglement. The aim of our entanglement concentration service is to provide reliable, high-quality entanglement for a dedicated set of quantum nodes in the quantum Internet.
Chapter
With the appearance of light field displays, users may enjoy a much more natural sensation of 3D experience compared to prior technologies. This type of autostereoscopic, glasses-free visualization allows medical applications to improve both in usability and efficiency. The high angular resolution of medical images is resource-consuming, but can on...
Article
Full-text available
We define the entanglement-gradient routing scheme for quantum repeater networks. The routing framework fuses the fundamentals of swarm intelligence and quantum Shannon theory. Swarm intelligence provides nature-inspired solutions for problem solving. Motivated by models of social insect behavior, the routing is performed using parallel threads to...
Article
Full-text available
PrefaceSince being established in 1949, the Faculty of Electrical Engineering and Informatics (VIK) BME has played a flagship role in the development of electronics, IT and computer science in Hungary. We are proud of combining engineering applications with sound scientific results, which is the assurance of high-level industrial collaboration lead...
Article
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In this paper we consider a wireless contextualization of the local routing protocol on scale-free networks embedded in a plane and analyze on the one hand how cooperation affects network efficiency, and on the other hand the stability of cooperation structures. Cooperation is interpreted on k-cliques as local exchange of topological information be...
Article
The second generation Continuous-Variable Quantum Key Distribution is one of the most promising application of quantum mechanics in communications. This paper investigates a state-of-the-art Continuous-Variable Quantum Key Distribution solution from circuit modeling point of view in order to build an appropriate simulation framework. This framework...
Article
Background: Radio Frequency Identification (RFID) technology is becoming ubiquitous, more and more applications use this technique. Most of them are applied for access control, supply chain or animal tagging, however, there are some, which stores confidential data about its owner (e.g., passport, credit card). Therefore, serious considerations shou...
Conference Paper
Angular resolution plays a vital role in the perceived quality when displaying visual content on autostereoscopic 3D displays, since it affects the motion parallax effect. In this paper, we present the results of a subjective quality assessment carried out on a light field display, investigating the perceptual quality of visual content with differe...
Article
Releasing connection data from social networking services can pose a significant threat to user privacy. In our work, we consider structural social network de-anonymization attacks, which are used when a malicious party uses connections in a public or other identified network to re-identify users in an anonymized social network release that he obta...
Conference Paper
The existing robust technique, Scalar Reconciliation combined with a Continuous-Variable Quantum Key Distribution is investigated in this paper with the help of simulations in terms of the symbol error rate. The solution contains efficient logical layer-based reconciliation for Continuous-Variable Quantum Key Distribution techniques, which extract...
Conference Paper
With the appearance of light field displays, users may enjoy a much more natural sensation of 3D experience compared to prior technologies. This type of autostereoscopic, glasses-free visualization allows medical applications to improve both in usability and efficiency. The high angular resolution of medical images is resource-consuming, but can on...
Conference Paper
We propose the Gaussian quadrature inference (GQI) method for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD protocol utilizes Gaussian subcarrier quantum continuous variables (CV) for information transmission. The GQI framework provides a minimal error estimate of the quadratures of the CV quantum states fr...
Conference Paper
We propose the adaptive quadrature detection for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD scheme uses Gaussian subcarrier continuous variables for the information conveying and Gaussian sub-channels for the transmission. The proposed multicarrier detection scheme dynamically adapts to the subchannel co...