A5102879737- Quantum Information and Cryptography
- Quantum Computing Algorithms and Architecture
- Quantum Mechanics and Applications
- Quantum optics and atomic interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Blockchain Technology Applications and Security
- Wireless Communication Security Techniques
- Cloud Computing and Resource Management
- IoT and Edge/Fog Computing
- Laser-Matter Interactions and Applications
- Quantum-Dot Cellular Automata
- Cryptographic Implementations and Security
- Advanced Fiber Laser Technologies
- Cryptography and Data Security
- Quantum and electron transport phenomena
- Mechanical and Optical Resonators
- Advanced Frequency and Time Standards
- Physical Unclonable Functions (PUFs) and Hardware Security
- Chaos-based Image/Signal Encryption
- DNA and Biological Computing
- Photorefractive and Nonlinear Optics
- Terahertz technology and applications
- Random lasers and scattering media
- Photonic and Optical Devices
University of York
2014-2024
Universitat Autònoma de Barcelona
2009-2013
University of Geneva
2009
Università di Camerino
2003-2006
Quantum cryptography is arguably the fastest growing area in quantum information science. Novel theoretical protocols are designed on a regular basis, security proofs constantly improving, and experiments gradually moving from proof-of-principle lab demonstrations to in-field implementations technological prototypes. In this review, we provide both general introduction state of art description recent advances field, theoretically experimentally. We start by reviewing key distribution based...
Abstract Quantum communications promises reliable transmission of quantum information, efficient distribution entanglement and generation completely secure keys. For all these tasks, we need to determine the optimal point-to-point rates that are achievable by two remote parties at ends a channel, without restrictions on their local operations classical communication, which can be unlimited two-way. These two-way assisted capacities represent ultimate reachable repeaters. Here, constructing...
Over the past six decades, computing systems field has experienced significant transformations, profoundly impacting society with transformational developments, such as Internet and commodification of computing. Underpinned by technological advancements, computer systems, far from being static, have been continuously evolving adapting to cover multifaceted societal niches. This led new paradigms cloud, fog, edge computing, Things (IoT), which offer fresh economic creative opportunities....
We present here an all-optical scheme for the experimental realization of a quantum phase gate. It is based on polarization degree freedom two traveling single-photon wave packets and exploits giant Kerr nonlinearities that can be attained in coherently driven ultracold atomic media.
We review recent results on the simulation of quantum channels, reduction adaptive protocols (teleportation stretching), and derivation converse bounds for private communication, as established in PLOB (Pirandola et al 2017 Nat. Commun. 8 15043). start by introducing a general weak bound communication based relative entropy entanglement. discuss how combining this with channel teleportation stretching, two-way capacities several fundamental including bosonic lossy channel. then provide...
We present a rigorous security analysis of continuous-variable measurement-device-independent quantum key distribution (CV MDI QKD) in finite-size scenario. The proof is obtained two steps: by first assessing the against collective Gaussian attacks, and then extending to most general class coherent attacks via de Finetti reduction. Our result combines recent state-of-the-art proofs for CV QKD with findings about min-entropy calculus parameter estimation. In doing so, we improve estimate...
We analyze the nonlinear optical response of a four-level atomic system driven into tripod configuration. The large cross-Kerr nonlinearities that occurr in such are shown to produce phase shift order $\pi$. Such substantial may be observed cold gas magneto-optical trap where it coupl fasibly exploited towards realization polarization quantum gate. experimental feasibility gate is here examined detail.
We study the impact of finite-size effects on key rate continuous-variable (CV) measurement-device-independent (MDI) quantum distribution (QKD), considering two-mode Gaussian attacks. Inspired by parameter estimation technique developed in Ruppert et al. [Phys. Rev. A 90, 062310 (2014)], we adapt it to CV-MDI-QKD and, assuming realistic experimental conditions, analyze rate. find that performance protocol approaches ideal one, increasing block size, most importantly, blocks between...
A well-known empirical rule for the demand of wireless communication systems is that Edholm's law bandwidth. It states bandwidth in short-range communications doubles every 18 months. With growing and decreasing cell size systems, terahertz (THz) are expected to become increasingly important modern day applications. this expectation comes need protecting users' privacy security best way possible. mind, we show quantum key distribution can operate THz regime derive relevant secret rates...
Traditional and lightweight cryptography primitives protocols are insecure against quantum attacks. Thus, a real-time application using traditional or does not ensure full-proof security. Post-quantum Cryptography is important for the Internet of Things (IoT) due to its security Quantum This paper offers broad literature analysis post-quantum IoT networks, including challenges research directions adopt in applications. The work draws focus towards cryptosystems that useful...
Advances in quantum computers may pose a significant threat to existing public-key encryption methods, which are crucial the current infrastructure of cyber security. Both RSA and ECDSA, two most widely used security algorithms today, be (in principle) solved by Shor algorithm polynomial time due its ability efficiently solve discrete logarithm problem, potentially making present infrastructures insecure against attack. The National Institute Standards Technology (NIST) reacted with...
The recent development of quantum computing, which makes use entanglement, superposition, and other fundamental concepts, has the ability to provide substantial processing advantages over traditional computing. These features help solve many hard problems that cannot be solved with computing methods. are in areas like modeling mechanics, logistics, making chemical-based advances, designing drugs, statistical science, sustainable energy, banking, reliable communication, chemical engineering....
We study the security of two-way quantum cryptography at different wavelengths electromagnetic spectrum, from optical down to microwave range. In particular, we consider a communication protocol where Gaussian-modulated thermal states are subject random Gaussian displacements and finally homodyned. show how its threshold (in reverse reconciliation) is extremely robust with respect preparation noise able outperform thresholds one-way protocols any wavelength. As result, improved distances now...
We consider the continuous-variable protocol of Pirandola et al. [Nature Photonics 9, 397-402 (2015), see also arXiv.1312.4104] where secret-key is established by measurement an untrusted relay. In this network protocol, two authorized parties are connected to relay insecure quantum links. Secret correlations generated a Bell detection performed on incoming coherent states. present work we provide detailed study symmetric configuration, midway between parties. analyze eavesdropping...
It is known that quantum scissors, as non-deterministic amplifiers, can enhance the performance of Gaussian-modulated continuous-variable key distribution (CV-QKD) in noisy and long-distance regimes operation. Here, we extend this result to a non-Gaussian CV-QKD protocol with discrete modulation. We show that, by using proper setting, use scissors receiver such discrete-modulation protocols would allow us achieve positive secret rates at high loss excess noise operation, which have been...
We investigate the use of quantum scissors, as candidates for non-deterministic amplifiers, in continuous-variable key distribution. Such devices rely on single-photon sources their operation and such, they do not necessarily preserve Guassianity channel. Using exact analytical modeling system components, we bound secret generation rate a protocol that uses scissors. find that, certain non-zero values excess noise, such can reach longer distances than counterpart with no amplification. This...
We present a full quantum treatment of five-level atomic system coupled to two and classical light fields. The fields undergo cross-phase-modulation induced by electromagnetically transparency. performance this configuration as two-qubit phase gate for traveling single photons is examined. A trade-off between the size conditional shift fidelity found. Nonetheless, satisfactory still found be possible in transient regime, corresponding fast operation.
One crucial step in any quantum key distribution (QKD) scheme is parameter estimation. In a typical QKD protocol the users have to sacrifice part of their raw data estimate parameters communication channel as, for example, error rate. This introduces trade-off between secret rate and accuracy estimation finite-size regime. Here we show that continuous-variable not subject this constraint as whole keys can be used both generation, without compromising security. First, property holds...
We consider the two-way quantum cryptographic protocol with coherent states assuming direct reconciliation. A detailed security analysis is performed considering a two-mode attack, that represents residual eavesdropping once parties have reduced general attack by applying symmetric random permutations. In this context we provide analytical expression for keyrate, discussing impact of correlations on scheme. particular identify optimal against communication, which given and separable correlations.
Abstract We consider two-way continuous-variable quantum key distribution, studying its security against general eavesdropping strategies. Assuming the asymptotic limit of many signals exchanged, we prove that Gaussian protocols are immune to coherent attacks. More precisely show superadditivity thresholds, which proven be higher than corresponding one-way counterparts in all cases. perform analysis first reducing a two-mode attack and then showing is achieved by exploiting random on/off...
We show that the adiabatic dynamics of a Bose-Einstein condensate (BEC) in double-well potential can be described terms dark variable resulting from combination population imbalance and spatial atomic coherence between two wells. By means this variable, we extend, to nonlinear matter-wave case, recent proposal by Vitanov Shore [Phys. Rev. A 73, 053402 (2006)] on passage techniques coherently control internal levels an atom or molecule. investigate conditions adiabatically split transport BEC...