Maciej Demianowicz - Publikacje - MOST Wiedzy

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Zdjęcie profilowe: dr hab. inż. Maciej Demianowicz

dr hab. inż. Maciej Demianowicz

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Rok 2022
  • Negative result about the construction of genuinely entangled subspaces from unextendible product bases
    Publikacja

    Unextendible product bases (UPBs) provide a versatile tool with various applications across different areas of quantum information theory. Their comprehensive characterization is thus of great importance and has been a subject of vital interest for over two decades now. An open question asks about the existence of UPBs, which are genuinely unextendible, i.e., they are not extendible even with biproduct vectors. In other words,...

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  • Universal construction of genuinely entangled subspaces of any size
    Publikacja

    We put forward a simple construction of genuinely entangled subspaces – subspaces supporting only genuinely multipartite entangled states – of any permissible dimensionality for any number of parties and local dimensions. The method uses nonorthogonal product bases, which are built from totally nonsingular matrices with a certain structure. We give an explicit basis for the constructed subspaces. An immediate consequence of our...

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Rok 2021
  • Simple sufficient condition for subspace to be completely or genuinely entangled
    Publikacja

    - NEW JOURNAL OF PHYSICS - Rok 2021

    We introduce a simple sufficient criterion, which allows one to tell whether a subspace of a bipartite or multipartite Hilbert space is entangled. The main ingredient of our criterion is a bound on the minimal entanglement of a subspace in terms of entanglement of vectors spanning that subspace expressed for geometrical measures of entanglement. The criterion is applicable to both completely and genuinely entangled subspaces. We...

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Rok 2020
  • An approach to constructing genuinely entangled subspaces of maximal dimension
    Publikacja

    Genuinely entangled subspaces (GESs) are the class of completely entangled subspaces that contain only genuinely multiparty entangled states. They constitute a particularly useful notion in the theory of entanglement but also have found an application, for instance, in quantum error correction and cryptography. In a recent study (Demianowicz and Augusiak in Phys Rev A 98:012313, 2018), we have shown how GESs can be efficiently...

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Rok 2019
Rok 2018
Rok 2015
  • Entanglement and Nonlocality are Inequivalent for Any Number of Parties
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2015

    Understanding the relation between nonlocality and entanglement is one of the fundamental problems in quantum physics. In the bipartite case, it is known that these two phenomena are inequivalent, as there exist entangled states of two parties that do not violate any Bell inequality. However, except for a single example of an entangled three-qubit state that has a local model, almost nothing is known about such a relation in multipartite...

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  • Inequivalence of entanglement, steering, and Bell nonlocality for general measurements
    Publikacja
    • M. Quintino
    • T. Vértesi
    • D. Cavalcanti
    • R. Augusiak
    • M. Demianowicz
    • A. Acín
    • N. Brunner

    - PHYSICAL REVIEW A - Rok 2015

    Einstein-Podolsky-Rosen steering is a form of inseparability in quantum theory commonly acknowledged to be intermediate between entanglement and Bell nonlocality. However, this statement has so far only been proven for a restricted class of measurements, namely, projective measurements. Here we prove that entanglement, one-way steering, two-way steering, and nonlocality are genuinely different considering general measurements,...

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  • Progress towards a unified approach to entanglement distribution
    Publikacja

    - PHYSICAL REVIEW A - Rok 2015

    Entanglement distribution is key to the success of secure communication schemes based on quantum mechanics, and there is a strong need for an ultimate architecture able to overcome the limitations of recent proposals such as those based on entanglement percolation or quantum repeaters. In this work we provide a broad theoretical background for the development of such technologies. In particular, we investigate the question of whether...

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Rok 2014
  • Elemental and tight monogamy relations in nonsignaling theories
    Publikacja

    - PHYSICAL REVIEW A - Rok 2014

    Physical principles constrain the way nonlocal correlations can be distributed among distant parties. These constraints are usually expressed by monogamy relations that bound the amount of Bell inequality violation observed among a set of parties by the violation observed by a different set of parties. We prove here that much stronger monogamy relations are possible for nonsignaling correlations by showing how nonlocal correlations...

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  • Local hidden–variable models for entangled quantum states
    Publikacja

    While entanglement and violation of Bell inequalities were initially thought to be equivalent quantum phenomena, we now have different examples of entangled states whose correlations can be described by local hidden-variable models and, therefore, do not violate any of the Bell inequalities. We provide an up-to-date overview of the existing literature regarding local hidden-variable models for entangled quantum states, in both...

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Rok 2013
  • Decoherence-free communication over multiaccess quantum channels

    In this paper we consider decoherence-free communication over multiple access and k-user quantum channels. First, we concentrate on a hermitian unitary noise model U for a two-access bi-unitary channel and show that in this case a decoherence-free code exists if the space of Schmidt matrices of an eigensubspace of U exhibits certain properties of decomposability. Then, we show that our technique is also applicable for generic random unitary...

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  • Multiacces quantum communication and product higher rank numerical range
    Publikacja

    In the present paper we initiate the study of the product higher rank numerical range. The latter, being a variant of the higher rank numerical range, is a natural tool for study- ing a construction of quantum error correction codes for multiple access channels. We review properties of this set and relate it to other numerical ranges, which were recently introduced in the literature. Further, the concept is applied to the construction...

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Rok 2011
Rok 2010
  • Aspects of multistation quantum information broadcasting

    We study quantum information transmission over multiparty quantum channel. In particular, we show an equivalence of different capacity notions and provide a multiletter characterization of a capacity region for a general quantum channel with k senders and m receivers. We point out natural generalizations to the case of two-way classical communication capacity. (C) 2010 Elsevier B.V. All rights reserved.

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Rok 2008
Rok 2006
  • Fidelity thresholds in single copy entanglement distillation

    Rozważono różne aspekty destylacji zaszumionego splątania oraz pewne stowarzyszone efekty w kwantowej korekcji błędów. W szczególności pokazano, że w przypadku gdy dozwolona jest komunikacja klasyczna w jedną stronę oraz współdzielony stan kwantowy dxd nie jest czysty, to istnieje próg dla optymalnego ułamka F stanu, który może być otrzymany w procesie destylacji na jednej kopii. Wynika z tego, że aby otrzymać (probabilistycznie)...

  • General construction of noiseless networks detecting entanglement with the help of linear maps

    W pracy zaprezentowano ogólny schemat konstrukcji bezszumowych sieci pozwalających wykrywać splątanie przy pomocy odwzorowań liniowych. Pokazano jak zastosować metodę do detekcji splątania nieznanego stanu bez jego wcześniejszej rekonstrukcji. W szczególności pokazano, że zawsze istnieje bezszumowa sieć pozwalająca wykrywać splątanie przy użyciu dodatnich, ale nie kompletnie dodatnich odwzorowań. Zaprezentowano także uogólnienie...

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  • Quantum channel capacities: multiparty communication

    Analizowane są różne aspekty wieloużytkownikowej komunikacji kwantowymi kanałami bez pamięci. Uogólnione zostały pewne znane rezultaty dotyczące komunikacji kwantowej w układzie jeden nadawca -jeden odbiorca. W szczególności pokazana została bezużyteczność komunikacji klasycznej ''w przód'' w procesie transmisji informacji kwantowej oraz równoważność definicji regionów pojemności opartych na różnych miarach wierności transmisji:...

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wyświetlono 2224 razy