Paweł Horodecki - Publikacje - MOST Wiedzy

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Rok 2007
  • 12 [Chapter]. Bound entanglement
    Publikacja

    - Rok 2007

    Kwantowe splątanie jest jednym z podstawowych elementów kwantowej teorii informacji. Jak wiadomo niskowymiarowe (2otimes 2 i 2otimes 3) splątane stany kwantowe są zawsze destylowalne. W wyższych wymiarach jednak istnieją stany, które mimo, że są splątane nie pozwalają na destylację. Ten rodzaj splątania, nazywany związanym, jest często trudny do wykrycia i pozornie bezużyteczny. Jak pokazują jednak liczne badania splątanie związane...

Rok 2010
  • A few steps more towards NPT bound entanglement
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2010

    In this paper, existence of bound entangled states with nonpositive partial transpose (NPT) is considered. As one knows, existence of such states would in particular imply nonadditivity of distillable entanglement. Moreover, it would rule out a simple mathematical description of the set of distillable states. The particular state, known to be 1-copy nondistillable and supposed to be bound entangled, is considered. The problem of...

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  • Are quantum correlations symmetric?
    Publikacja

    - QUANTUM INFORMATION & COMPUTATION - Rok 2010

    We provide operational definition of symmetry of entanglement: An entangled state contains symmetric entanglement if its subsystems can be exchanged (swapped) by means of local operations and classical communication. We show that in general states have asymmetric entanglement. This allows to construct nonsymmetric measure of entanglement, and a parameter that reports asymmetry of entanglement contents of quantum state. We propose...

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  • 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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  • Efficient bounds on quantum-communication rates via their reduced variants
    Publikacja

    - PHYSICAL REVIEW A - Rok 2010

    We investigate one-way communication scenarios where Bob operating on his component can transfer some subsystem to the environment. We define reduced versions of quantum-communication rates and, further, prove upper bounds on a one-way quantum secret key, distillable entanglement, and quantum-channel capacity by means of their reduced versions. It is shown that in some cases they drastically improve their estimation.

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Rok 2009
  • A simple test for quantum channel capacity
    Publikacja

    Based on state and channel isomorphism we point out that semidefiniteprogramming can be used as a quick test for nonzero one-way quantum channelcapacity. This can be achieved by searching for symmetric extensions of statesisomorphic to a given quantum channel. With this method we provide examplesof quantum channels that can lead to high entanglement transmission but stillhave zero one-way capacity, in particular, regions of symmetric...

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  • Broadcast copies reveal the quantumness of correlations
    Publikacja

    - PHYSICAL REVIEW A - Rok 2009

    We study the quantumness of bipartite correlations by proposing a quantity that combines a measure of total correlations-mutual information-with the notion of broadcast copies-i.e., generally nonfactorized copies-of bipartite states. By analyzing how our quantity increases with the number of broadcast copies, we are able to classify classical, separable, and entangled states. This motivates the definition of the broadcast regularization...

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  • General paradigm for distilling classical key from quantum states
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 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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  • Inseparability criteria based on matrices of moments
    Publikacja

    - PHYSICAL REVIEW A - Rok 2009

    Inseparability criteria for continuous and discrete bipartite quantum states based on moments of annihilationand creation operators are studied by developing the idea of Shchukin-Vogel criterion Phys. Rev. Lett. 95,230502 2005. If a state is separable, then the corresponding matrix of moments is separable too. Thus, wederive generalized criteria based on the separability properties of the matrix of moments. In particular, acriterion...

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Rok 2011
  • All Nonclassical Correlations Can Be Activated into Distillable Entanglement
    Publikacja
    • M. Piani
    • S. Gharibian
    • G. Adesso
    • J. Calsamigilia
    • P. Horodecki
    • A. Winter

    - PHYSICAL REVIEW LETTERS - Rok 2011

    We devise a protocol in which general nonclassical multipartite correlations produce a physically relevant effect, leading to the creation of bipartite entanglement. In particular, we show that the relative entropy of quantumness, which measures all nonclassical correlations among subsystems of a quantum system, is equivalent to and can be operationally interpreted as the minimum distillable entanglement generated between the system...

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  • Collective Uncertainty Entanglement Test
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2011

    For a given pure state of a composite quantum system we analyze the product of its projections onto aset of locally orthogonal separable pure states. We derive a bound for this product analogous to theentropic uncertainty relations. For bipartite systems the bound is saturated for maximally entangled statesand it allows us to construct a family of entanglement measures, we shall call collectibility. As thesequantities are experimentally...

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  • Experimental Extraction of Secure Correlations from a Noisy Private State
    Publikacja
    • K. Dobek
    • M. Karpiński
    • R. Demkowicz-Dobrzański
    • K. Banaszek
    • P. Horodecki

    - PHYSICAL REVIEW LETTERS - Rok 2011

    We report experimental generation of a noisy entangled four-photon state that exhibits a separation between the secure key contents and distillable entanglement, a hallmark feature of the recently established quantum theory of private states. The privacy analysis, based on the full tomographic reconstruction of the prepared state, is utilized in a proof-of-principle key generation. The inferiority of distillation-based strategies...

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Rok 2017
  • Amplifying the Randomness of Weak Sources Correlated With Devices
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2017

    The problem of device-independent randomness amplification against no-signaling adversaries has so far been studied under the assumption that the weak source of randomness is uncorrelated with the (quantum) devices used in the amplification procedure. In this paper, we relax this assumption, and reconsider the original protocol of Colbeck and Renner using a Santha-Vazirani (SV) source. To do so, we introduce an SV-like condition...

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  • Generic appearance of objective results in quantum measurements
    Publikacja

    - PHYSICAL REVIEW A - Rok 2017

    Measurement is of central interest in quantum mechanics as it provides the link between the quantum world and the world of everyday experience. One of the features of everyday experience is its robust, objective character, contrasting the delicate nature of quantum systems. Here we analyze in a completely model-independent way the celebrated von Neumann measurement process, using recent techniques of information flow, studied in...

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  • Information content of systems as a physical principle
    Publikacja

    - PHYSICAL REVIEW A - Rok 2017

    To explain the conceptual gap between classical and quantum and other, hypothetical descriptions of the world, several principles have been proposed. So far, all these principles have not explicitly included the uncertainty relation. Here we introduce an information content principle ( ICP ) which represents a constrained uncertainty principle. The principle, by taking into account the encoding and decoding properties of a single physical...

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Rok 2012
  • Analytical progress on symmetric geometric discord: Measurement-based upper bounds
    Publikacja

    - PHYSICAL REVIEW A - Rok 2012

    Quantum correlations may be measured by means of the distance of the state to the subclass ofstates having well defined classical properties. In particular, a geometric measure of asymmetricdiscord [Daki´c et al., Phys. Rev. Lett. 105, 190502 (2010)] was recently defined as the Hilbert-Schmidt distance of a given two-qubit state to the closest classical-quantum (CQ) correlated state.We analyze a geometric measure of symmetric...

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  • Convergence to equilibrium under a random Hamiltonian
    Publikacja
    • F. G. Brandao
    • P. Ćwikliński
    • M. Horodecki
    • P. Horodecki
    • J. Korbicz
    • M. Mozrzymas

    - PHYSICAL REVIEW E - Rok 2012

    We analyze equilibration times of subsystems of a larger system under a random total Hamiltonian, in which the basis of the Hamiltonian is drawn from the Haar measure. We obtain that the time of equilibration is of the order of the inverse of the arithmetic average of the Bohr frequencies. To compute the average over a random basis, we compute the inverse of a matrix of overlaps of operators which permute four systems. We first...

  • Directed percolation effects emerging from superadditivity of quantum networks

    Entanglement-induced nonadditivity of classical communication capacity in networks consisting of quantum channels is considered. Communication lattices consisting of butterfly-type entanglement-breaking channels augmented, with some probability, by identity channels are analyzed. The capacity superadditivity in the network is manifested in directed correlated bond percolation which we consider in two flavors: simply directed and...

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Rok 2013
  • Anomalous decay of quantum correlations of quantum-dot qubits
    Publikacja

    - PHYSICAL REVIEW A - Rok 2013

    We study the evolution of quantum correlations, quantified by the geometric discord, of two excitonic quantum-dot qubits under the influence of the phonon environment. We show that the decay of these correlations differs substantially from the decay of entanglement. Instead of displaying sudden-death-type behavior, the geometric discord shows a tendency to undergo transitions between different types of decay, is sensitive to nonlocal...

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  • Conjectured strong complementary-correlations tradeoff
    Publikacja
    • A. Grudka
    • M. Horodecki
    • P. Horodecki
    • R. Horodecki
    • W. Kłobus
    • Ł. Pankowski

    - PHYSICAL REVIEW A - Rok 2013

    We conjecture uncertainty relations that restrict correlations between the results of measurements performed by two separate parties on a shared quantum state. The first uncertainty relation bounds the sum of two mutual informations when one party measures a single observable and the other party measures one of two observables. The uncertainty relation does not follow from the Maassen-Uffink uncertainty relation and is much stronger...

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  • Experimental generation of complex noisy photonic entanglement
    Publikacja
    • K. Dobek
    • M. Karpiński
    • R. Demkowicz-Dobrzański
    • K. Banaszek
    • P. Horodecki

    - LASER PHYSICS - Rok 2013

    We present an experimental scheme based on spontaneous parametric down-conversion to produce multiple-photon pairs in maximally entangled polarization states using an arrangement of two type-I nonlinear crystals. By introducing correlated polarization noise in the paths of the generated photons we prepare mixed-entangled states whose properties illustrate fundamental results obtained recently in quantum information theory, in particular those...

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Rok 2018
Rok 2008
  • Beyond the standard entropic inequalities: stronger scalar separability criteria and their applications

    Niedawno pokazano, że jeżeli dwupodukładowy stan kwantowy spełnia strukturalne kryterium separowalności oparte na pewnym liniowym odwzorowaniu dodatnim (tzw. odwzorowanie redukcyjne) to musi także spełniać skalarne kryterium separowalności oparte na nierównościach entropijnych. Ponieważ nierówności te są obiecującymi z eksperymentalnego punktu widzenia detektorami splątania w układach kwantowych, interesującym wydaje się pytanie...

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  • Entanglement-redistribution boxes
    Publikacja

    - PHYSICAL REVIEW A - Rok 2008

    We establish a framework to study the classical-communication properties of primitive local operations assisted by classical communication which realize various redistributions of entanglement, like, e.g., entanglement swapping. On the one hand, we analyze what local operations and how much classical communication are needed to perform them. On the other hand, we investigate whether and to what extent such primitives can help to...

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  • Entanglement-swapping boxes and their communication properties
    Publikacja

    - PHYSICAL REVIEW A - Rok 2008

    We pose the fundamental question of communication properties of primitives irrespectively of their implementation. To illustrate the idea we introduce the concept of entanglement-swapping boxes, i.e., we consider any quantum operations which perform entanglement swapping, not necessarily via simple quantum teleportation. We ask a question about the properties of such boxes, i.e., what local operations and how much classical communication...

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Rok 2020
Rok 2003
Rok 2006
Rok 2015
  • Bound on Bell inequalities by fraction of determinism and reverse triangle inequality
    Publikacja
    • P. Joshi
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • R. Horodecki
    • B. Li
    • S. Szarek
    • T. Szarek

    - PHYSICAL REVIEW A - Rok 2015

    It is an established fact that entanglement is a resource. Sharing an entangled state leads to nonlocal correlations and to violations of Bell inequalities. Such nonlocal correlations illustrate the advantage of quantum resources over classical resources. In this paper, we quantitatively study Bell inequalities with 2 × n inputs. As found in Gisin et al. [Int. J. Quantum. Inform. 05, 525 (2007)], quantum mechanical correlations...

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  • Distributed correlations and information flows within a hybrid multipartite quantum-classical system
    Publikacja

    - PHYSICAL REVIEW A - Rok 2015

    Understanding the non-Markovian mechanisms underlying the revivals of quantum entanglement in the presence of classical environments is central in the theory of quantum information. Tentative interpretations have been given by either the role of the environment as a control device or the concept of hidden entanglement. We address this issue from an information-theoretic point of view. To this aim, we consider a paradigmatic tripartite...

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  • Generic emergence of classical features in quantum Darwinism
    Publikacja

    - Nature Communications - Rok 2015

    Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics:...

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Rok 2014
  • Can Communication Power of Separable Correlations Exceed That of Entanglement Resource?
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2014

    The scenario of remote state preparation with a shared correlated quantum state and one bit of forward communication [B. Dakić et al., Nat. Phys. 8, 666 (2012)] is considered. Optimization of the transmission efficiency is extended to include general encoding and decoding strategies. The importance of the use of linear fidelity is recognized. It is shown that separable states cannot exceed the efficiency of entangled states by...

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  • Characterizing the Performance of <span class="sc">xor</span> Games and the Shannon Capacity of Graphs
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2014

    In this Letter we give a set of necessary and sufficient conditions such that quantum players of a two-party xor game cannot perform any better than classical players. With any such game, we associate a graph and examine its zero-error communication capacity. This allows us to specify a broad new class of graphs for which the Shannon capacity can be calculated. The conditions also enable the parametrization of new families of games...

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  • Constructive entanglement test from triangle inequality
    Publikacja

    - Journal of Physics A-Mathematical and Theoretical - Rok 2014

    We derive a simple lower bound on the geometric measure of entanglement for mixed quantum states in the case of a general multipartite system. The main ingredient of the presented derivation is the triangle inequality applied to the root infidelity distance in the space of density matrices. The obtained bound leads to entanglement criteria with a straightforward interpretation. The proposed criteria provide an experimentally accessible,...

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  • Free randomness amplification using bipartite chain correlations
    Publikacja
    • A. Grudka
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • M. Pawłowski
    • R. Ramanathan

    - PHYSICAL REVIEW A - Rok 2014

    A direct analysis of the task of randomness amplification from Santha-Vazirani sources using the violation of the chained Bell inequality is performed in terms of the convex combination of no-signaling boxes required to simulate quantum violation of the inequality. This analysis is used to find the exact threshold value of the initial randomness parameter from which perfect randomness can be extracted in the asymptotic limit of...

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  • Intrinsic asymmetry with respect to adversary: a new feature of Bell inequalities
    Publikacja

    - Journal of Physics A-Mathematical and Theoretical - Rok 2014

    It is known that the local bound of a Bell inequality is sensitive to the knowledge of the external observer about the settings statistics. Here we ask how that sensitivity depends on the structure of that knowledge. It turns out that in some cases it may happen that the local bound is much more sensitive to the adversaryʼs knowledge about the settings of one party than the other. Remarkably, there are Bell inequalities which are...

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Rok 2002
  • Concurrence in arbitrary dimensions
    Publikacja

    - JOURNAL OF MODERN OPTICS - Rok 2002

    Podano definicję kwantowej zgodności dla stanów dwucząstkowych w przypadku dowolnych skończonych wymiarów przestrzeni Hilberta. Wprowadzono także bi-zgodność, której znikanie stanowi warunek konieczny i dostateczny separowalności stanów dwucząstkowych.

  • Direct detection of quantum entanglement
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2002

    Basing on positive maps separability criterion we propose the experimentally viable, direct detection of quantum entanglement. It is efficient and does not require any a priori knowledge about the state. For two qubits it provides a sharp (i.e., “if and only if”) separability test and estimation of amount of entanglement. We view this method as a new form of quantum computation, namely, as a decision problem with quantum data structure.

  • Direct estimation of linear and nonlinear functionals of quantum state
    Publikacja
    • A. Ekert
    • C. M. Alves
    • D. K. Oi
    • M. Horodecki
    • P. Horodecki
    • L. C. Kwek

    - PHYSICAL REVIEW LETTERS - Rok 2002

    We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of...

  • Dynamical description of quantum computing: generic nonlocality of quantumnoise
    Publikacja

    We develop a dynamical non-Markovian description of quantum computing in the weak-coupling limit, in the lowest-order approximation. We show that the long-range memory of the quantum reservoir (such as the 1/t4 one exhibited by electromagnetic vacuum) produces a strong interrelation between the structure of noise and the quantum algorithm, implying nonlocal attacks of noise. This shows that the implicit assumption of quantum error...

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  • Dynamics of quantum entanglement
    Publikacja

    - PHYSICAL REVIEW A - Rok 2002

    A model of discrete dynamics of entanglement of a bipartite quantum state is considered. It involves a global unitary dynamics of the system and periodic actions of local bistochastic or decaying channel. For initially pure states the decay of entanglement is accompanied by an increase of von Neumann entropy of the system. We observe and discuss revivals of entanglement due to unitary interaction of subsystems. For some mixed states...

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Rok 2005
  • Direct measurement of nonlinear properties of bipartite quantum states
    Publikacja
    • F. A. Bovino
    • G. Castagnoli
    • A. Ekert
    • P. Horodecki
    • C. M. Alves
    • A. V. Sergienko

    - Rok 2005

    Nieliniowe własności stanów kwantowych, takie jak entropia, splątania, określają ilość ważnych fizycznych źródeł i są często używane w informatyce kwantowej. Na ogół są one obliczane z pełnego opisu stanu kwantowego, pomimo tego, że zależą od niewielkiej ilości parametrów opisujących dany stan. Wyciągamy nielokalną i nieliniową wielkość, mianowicie entropię Renyi, z lokalnych pomiarów dwóch par fotonów splątanych polaryzacyjnie.

Rok 2022
  • Hybrid no-signaling-quantum correlations
    Publikacja

    Fundamental investigations in non-locality have shown that while the no-signaling principle alone is not sufficient to single out the set of quantum non-local correlations, local quantum mechanics and no-signaling together exactly reproduce the set of quantum correlations in the two-party Bell scenario. Here, we introduce and study an intermediate hybrid no-signaling quantum set of non-local correlations that we term HNSQ in the...

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