339,816 research outputs found
Post-quantum cryptographic hardware primitives
The development and implementation of post-quantum cryptosystems have become a pressing issue in the design of secure computing systems, as general quantum computers have become more feasible in the last two years. In this work, we introduce a set of hardware post-quantum cryptographic primitives (PCPs) consisting of four frequently used security components, i.e., public-key cryptosystem (PKC), key exchange (KEX), oblivious transfer (OT), and zero-knowledge proof (ZKP). In addition, we design a high speed polynomial multiplier to accelerate these primitives. These primitives will aid researchers and designers in constructing quantum-proof secure computing systems in the post-quantum era.Published versio
Automated Verification of Quantum Protocols using MCMAS
We present a methodology for the automated verification of quantum protocols
using MCMAS, a symbolic model checker for multi-agent systems The method is
based on the logical framework developed by D'Hondt and Panangaden for
investigating epistemic and temporal properties, built on the model for
Distributed Measurement-based Quantum Computation (DMC), an extension of the
Measurement Calculus to distributed quantum systems. We describe the
translation map from DMC to interpreted systems, the typical formalism for
reasoning about time and knowledge in multi-agent systems. Then, we introduce
dmc2ispl, a compiler into the input language of the MCMAS model checker. We
demonstrate the technique by verifying the Quantum Teleportation Protocol, and
discuss the performance of the tool.Comment: In Proceedings QAPL 2012, arXiv:1207.055
Dynamics of quantum correlations in two-qubit systems within non-Markovian environments
Knowledge of the dynamical behavior of correlations with no classical
counterpart, like entanglement, nonlocal correlations and quantum discord, in
open quantum systems is of primary interest because of the possibility to
exploit these correlations for quantum information tasks. Here we review some
of the most recent results on the dynamics of correlations in bipartite systems
embedded in non-Markovian environments that, with their memory effects,
influence in a relevant way the system dynamics and appear to be more
fundamental than the Markovian ones for practical purposes. Firstly, we review
the phenomenon of entanglement revivals in a two-qubit system for both
independent environments and a common environment. We then consider the
dynamics of quantum discord in non-Markovian dephasing channel and briefly
discuss the occurrence of revivals of quantum correlations in classical
environments.Comment: 20 pages, 4 figures. Review article, in press in Int. J. Mod. Phys.
B, special issue "Classical Vs Quantum correlations in composite systems",
edited by L. Amico, S. Bose, V. Korepin and V. Vedra
Relations between entanglement and purity in non-Markovian dynamics
Knowledge of the relationships among different features of quantumness, like
entanglement and state purity, is important from both fundamental and practical
viewpoints. Yet, this issue remains little explored in dynamical contexts for
open quantum systems. We address this problem by studying the dynamics of
entanglement and purity for two-qubit systems using paradigmatic models of
radiation-matter interaction, with a qubit being isolated from the environment
(spectator configuration). We show the effects of the corresponding local
quantum channels on an initial two-qubit pure entangled state in the
concurrence-purity diagram and find the conditions which enable dynamical
closed formulas of concurrence, used to quantify entanglement, as a function of
purity. We finally discuss the usefulness of these relations in assessing
entanglement and purity thresholds which allow noisy quantum teleportation. Our
results provide new insights about how different properties of composite open
quantum systems behave and relate each other during quantum evolutions.Comment: 16 Pages, 10 Figures. One author added. Improved version with more
references and comment
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