Search results for: quantum cryptography - MOST Wiedzy

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Search results for: quantum cryptography

Search results for: quantum cryptography

  • On quantum cryptography with bipartite bound entangled states

    Publication

    Ostatnio pokazano bezpośrednie zastosowanie splątania związanego w kryptografii kwantowej. W niniejszym artykule dokonano przeglądu niektórych najnowszych osiągnięć dotyczących tego zagadnienia. W szczególności przypomniano istotne pojęcia i definicje. Ponadto podano nową konstrukcję stanów o splątaniu związanym, posiadających bezpieczne korelacje, dostarczając w ten sposób niskowymiarowe (6x6) stany o splątaniu związanym z niezerowym...

  • Experimentally feasible semi-device-independent certification of four-outcome positive-operator-valued measurements

    Publication

    - PHYSICAL REVIEW A - 2019

    Recently the quantum information science community devoted a lot of attention to the theoretical and practical aspects of generalized measurements, the formalism of all possible quantum operations leading to acquisition of classical information. On the other hand, due to imperfections present in quantum devices, and limited thrust to them, a trend of formulating quantum information tasks in a semi-device-independent manner emerged....

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  • Quantum entanglement

    Publication

    - REVIEWS OF MODERN PHYSICS - 2009

    All our former experience with application of quantum theory seems to say that what is predicted by quantum formalism must occur in the laboratory. But the essence of quantum formalism-entanglement, recognized by Einstein, Podolsky, Rosen, and Schrödinger-waited over 70 years to enter laboratories as a new resource as real as energy. This holistic property of compound quantum systems, which involves nonclassical correlations between...

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  • Constructing genuinely entangled multipartite states with applications to local hidden variables and local hidden states models

    Publication

    - PHYSICAL REVIEW A - 2018

    Building upon the results of R. Augusiak et al. [Phys. Rev. Lett. 115, 030404 (2015)] we develop a general approach to the generation of genuinely entangled multipartite states of any number of parties from genuinely entangled states of a fixed number of parties, in particular, the bipartite entangled ones. In our approach, certain isometries whose output subspaces are either symmetric or genuinely entangled in some multipartite...

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  • Unconditional privacy over channels which cannot convey quantum information

    Publication
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • D. Leung
    • J. Oppenheim

    - PHYSICAL REVIEW LETTERS - 2008

    Quantum cryptography enables one to verify that the state of the quantum system has not been tampered with and thus one can obtain privacy regardless of the power of the eavesdropper. All previous protocols relied on the ability to faithfully send quantum states or equivalently to share pure entanglement. Here we show this need not be the case-one can obtain verifiable privacy even through some channels which cannot be used to...

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  • Jerzy Konorski dr hab. inż.

    Jerzy Konorski received his M. Sc. degree in telecommunications from Gdansk University of Technology, Poland, and his Ph. D. degree in computer science from the Polish Academy of Sciences, Warsaw, Poland. In 2007, he defended his D. Sc. thesis at the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology. He has authored over 150 papers, led scientific projects funded by the European Union,...

  • Long-distance quantum communication over noisy networks without long-time quantum memory

    Publication
    • P. Mazurek
    • A. Grudka
    • M. Horodecki
    • P. Horodecki
    • J. Łodyga
    • Ł. Pankowski
    • A. Przysiężna

    - PHYSICAL REVIEW A - 2014

    The problem of sharing entanglement over large distances is crucial for implementations of quantum cryptography. A possible scheme for long-distance entanglement sharing and quantum communication exploits networks whose nodes share Einstein-Podolsky-Rosen (EPR) pairs. In Perseguers et al. [Phys. Rev. A 78, 062324 (2008)] the authors put forward an important isomorphism between storing quantum information in a dimension D and transmission...

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  • Multipartite secret key distillation and bound entanglement

    Recently it has been shown that quantum cryptography beyond pure entanglement distillation is possible and a paradigm for the associated protocols has been established. Here we systematically generalize the whole paradigm to the multipartite scenario. We provide constructions of new classes of multipartite bound entangled states, i.e., those with underlying twisted Greenberger-Horne-Zeilinger (GHZ) structure and nonzero distillable...

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  • Applications of semi-definite optimization in quantum information protocols

    Publication

    - 2016

    This work is concerned with the issue of applications of the semi-definite programming (SDP) in the field of quantum information sci- ence. Our results of the analysis of certain quantum information protocols using this optimization technique are presented, and an implementation of a relevant numerical tool is introduced. The key method used is NPA discovered by Navascues et al. [Phys. Rev. Lett. 98, 010401 (2007)]. In chapter...

  • Entanglement of genuinely entangled subspaces and states: Exact, approximate, and numerical results

    Publication

    - PHYSICAL REVIEW A - 2019

    Genuinely entangled subspaces (GESs) are those subspaces of multipartite Hilbert spaces that consist only of genuinely multiparty entangled pure states. They are natural generalizations of the well-known notion of completely entangled subspaces, which by definition are void of fully product vectors. Entangled subspaces are an important tool of quantum information theory as they directly lead to constructions of entangled states,...

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  • Paweł Horodecki prof. dr hab.

  • General paradigm for distilling classical key from quantum states

    Publication

    - IEEE TRANSACTIONS ON INFORMATION THEORY - 2009

    In this paper, we develop a formalism for distilling aclassical key from a quantum state in a systematic way, expandingon our previous work on a secure key from bound entanglement(Horodecki et al., 2005). More detailed proofs, discussion, andexamples are provided of the main results. Namely, we demonstratethat all quantum cryptographic protocols can be recast in away which looks like entanglement theory, with the only changebeing...

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  • Low-dimensional bound entanglement with one-way distillable cryptographic key

    Publication

    - IEEE TRANSACTIONS ON INFORMATION THEORY - 2008

    In this paper, we provide a class of bound entangled states that have positive distillable secure key rate. The smallest state of this kind is 4 circle times 4, which shows that peculiar security contained in bound entangled states does not need high-dimensional systems. We show that for these states a positive key rate can be obtained by one-way Devetak-Winter (DW) protocol. Subsequently, the volume of bound entangled key-distillable...