%0 Conference Paper
%B 2020 IEEE International Symposium on Information Theory (ISIT)2020 IEEE International Symposium on Information Theory (ISIT)
%D 2020
%T General Mixed State Quantum Data Compression with and without Entanglement Assistance
%A Khanian, Zahra Baghali
%A Winter, Andreas
%B 2020 IEEE International Symposium on Information Theory (ISIT)2020 IEEE International Symposium on Information Theory (ISIT)
%I IEEE
%C Los Angeles, CA, USA
%U https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=9166581https://ieeexplore.ieee.org/document/9174148/http://xplorestaging.ieee.org/ielx7/9166581/9173928/09174148.pdf?arnumber=9174148
%R 10.1109/ISIT44484.202010.1109/ISIT44484.2020.9174148
%0 Journal Article
%J Physical Review A
%D 2018
%T Gaussian quantum resource theories
%A Lami, Ludovico
%A Regula, Bartosz
%A Wang, Xin
%A Nichols, Rosanna
%A Winter, Andreas
%A Adesso, Gerardo
%B Physical Review A
%V 987
%8 Jan-08-2018
%U https://link.aps.org/doi/10.1103/PhysRevA.98.022335http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevA.98.022335/fulltexthttps://link.aps.org/article/10.1103/PhysRevA.98.022335
%! Phys. Rev. A
%R 10.1103/PhysRevA.98.022335
%0 Journal Article
%J Journal of Physics A: Mathematical and Theoretical
%D 2018
%T A generalized wave-particle duality relation for finite groups
%A Bagan, Emilio
%A John Calsamiglia
%A Bergou, János A
%A Hillery, Mark
%B Journal of Physics A: Mathematical and Theoretical
%V 51
%P 414015
%8 Dec-10-2018
%! J. Phys. A: Math. Theor.
%R 10.1088/1751-8121/aabb21
%0 Journal Article
%J Reports on Progress in Physics
%D 2018
%T Genuine quantum correlations in quantum many-body systems: a review of recent progress
%A De Chiara, Gabriele
%A Sanpera, Anna
%B Reports on Progress in Physics
%V 81
%P 074002
%8 Jan-07-2018
%! Rep. Prog. Phys.
%R 10.1088/1361-6633/aabf61
%0 Journal Article
%J Nature Communications
%D 2017
%T Generalized laws of thermodynamics in the presence of correlations
%A Bera, Manabendra N.
%A Riera, Arnau
%A Lewenstein, Maciej
%A Winter, Andreas
%B Nature Communications
%V 8
%8 Jan-12-2017
%U http://www.nature.com/articles/s41467-017-02370-xhttp://www.nature.com/articles/s41467-017-02370-x.pdfhttp://www.nature.com/articles/s41467-017-02370-x.pdfhttp://www.nature.com/articles/s41467-017-02370-x
%! Nat Commun
%R 10.1038/s41467-017-02370-x
%0 Journal Article
%J JOURNAL OF MATHEMATICAL PHYSICS
%D 2017
%T Genuine-multipartite entanglement criteria based on positive maps
%A Clivaz, Fabien
%A Huber, Marcus
%A Lami, Ludovico
%A Murta, Glaucia
%X Positive maps applied to a subsystem of a bipartite quantum state constitute a central tool in characterising entanglement. In the multipartite case, however, the direct application of a positive but not completely positive map cannot distinguish if a state is genuinely multipartite entangled or just entangled across some bipartition. We thus generalise this bipartite concept to the multipartite setting by introducing non-positive maps that are positive on the subset of biseparable states but can map to a non-positive element if applied to a genuine multipartite entangled state. We explicitly construct examples of multipartite non-positive maps, obtained from positive maps via a lifting procedure, that in this fashion can reveal genuine multipartite entanglement in a robust way. Published by AIP Publishing.
%B JOURNAL OF MATHEMATICAL PHYSICS
%V 58
%8 aug
%R 10.1063/1.4998433
%0 Journal Article
%J NEW JOURNAL OF PHYSICS
%D 2017
%T Global and local thermometry schemes in coupled quantum systems
%A Campbell, Steve
%A Mehboudi, Mohammad
%A De Chiara, Gabriele
%A Paternostro, Mauro
%X We study the ultimate bounds on the estimation of temperature for an interacting quantum system. We consider two coupled bosonic modes that are assumed to be thermal and using quantum estimation theory establish the role the Hamiltonian parameters play in thermometry. We show that in the case of a conserved particle number the interaction between the modes leads to a decrease in the overall sensitivity to temperature, while interestingly, if particle exchange is allowed with the thermal bath the converse is true. We explain this dichotomy by examining the energy spectra. Finally, we devise experimentally implementable thermometry schemes that rely only on locally accessible information from the total system, showing that almost Heisenberg limited precision can still be achieved, and we address the (im)possibility for multiparameter estimation in the system.
%B NEW JOURNAL OF PHYSICS
%V 19
%8 oct
%R 10.1088/1367-2630/aa7fac
%0 Journal Article
%J New Journal of Physics
%D 2015
%T A geometric approach to quantum state separation
%A E. Bagan
%A Yerokhin, V.
%A Shehu, A.
%A Feldman, E.
%A Bergou, J. A.
%X Probabilistic quantum state transformations can be characterized by the degree of state separation they provide. This, in turn, sets limits on the success rate of these transformations. We consider optimum state separation of two known pure states in the general case where the known states have arbitrary a priori probabilities. The problem is formulated from a geometric perspective and shown to be equivalent to the problem of finding tangent curves within two families of conics that represent the unitarity constraints and the objective functions to be optimized, respectively. We present the corresponding analytical solutions in various forms. In the limit of perfect state separation, which is equivalent to unambiguous state discrimination, the solution exhibits a phenomenon analogous to a second order symmetry breaking phase transition. We also propose a linear optics implementation of separation which is based on the dual rail representation of qubits and single-photon multiport interferometry.
%B New Journal of Physics
%V 17
%P 123015
%G eng
%U http://stacks.iop.org/1367-2630/17/i=12/a=123015
%0 Journal Article
%J Proceedings of the National Academy of Sciences
%D 2014
%T Generation and confirmation of a (100 x 100)-dimensional entangled quantum system
%A Krenn, M.
%A Huber, M
%A Fickler, R.
%A Lapkiewicz, R.
%A Ramelow, S.
%A Zeilinger, A.
%X Entangled quantum systems have properties that have fundamentally overthrown the classical worldview. Increasing the complexity of entangled states by expanding their dimensionality allows the implementation of novel fundamental tests of nature, and moreover also enables genuinely new protocols for quantum information processing. Here we present the creation of a (100x100)-dimensional entangled quantum system, using spatial modes of photons. For its verification we develop a novel nonlinear criterion which infers entanglement dimensionality of a global state by using only information about its subspace correlations. This allows very practical experimental implementation as well as highly efficient extraction of entanglement dimensionality information. Applications in quantum cryptography and other protocols are very promising.
%B Proceedings of the National Academy of Sciences
%V 111
%P 6243 - 6247
%8 04/2014
%N 17
%! Proceedings of the National Academy of Sciences
%R 10.1073/pnas.1402365111
%0 Journal Article
%J Physical Review Letters
%D 2014
%T Graph-Theoretic Approach to Quantum Correlations
%A Cabello, Adán
%A Severini, Simone
%A Winter, Andreas
%B Physical Review Letters
%V 112
%P 040401
%8 1/2014
%N 4
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.112.040401
%0 Conference Paper
%B 9th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2014)
%D 2014
%T Graph-theoretical Bounds on the Entangled Value of Non-local Games
%A Chailloux, André
%A Mančinska, Laura
%A Scarpa, Giannicola
%A Severini, Simone
%E Flammia, Steven T.
%E Harrow, Aram W.
%B 9th Conference on the Theory of Quantum Computation, Communication and Cryptography (TQC 2014)
%I Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik
%C Dagstuhl, Germany
%@ 978-3-939897-73-6
%U http://drops.dagstuhl.de/opus/volltexte/2014/4807
%R 10.4230/LIPIcs.TQC.2014.67
%0 Journal Article
%J New J. Phys.
%D 2012
%T Glass to superfluid transition in dirty bosons on a lattice
%A Julia Stasińska
%A Massignan, Pietro
%A Bishop, Michael
%A Wehr, Jan
%A Sanpera, Anna
%A Lewenstein, Maciej
%X We investigate the interplay between disorder and interactions in a Bose gas on a lattice in presence of randomly localized impurities. We compare the performance of two theoretical methods, the simple version of multi-orbital Hartree-Fock and the common Gross-Pitaevskii approach, showing how the former gives a very good approximation to the ground state in the limit of weak interactions, where the superfluid fraction is small. We further prove rigorously that for this class of disorder the fractal dimension of the ground state d* tends to the physical dimension in the thermodynamic limit. This allows us to introduce a quantity, the fractional occupation, which gives insightful information on the crossover from a Lifshits to a Bose glass. Finally, we compare temperature and interaction effects, highlighting similarities and intrinsic differences.
%B New J. Phys.
%V 14
%P 043043
%U http://arxiv.org/abs/1111.3494
%R 10.1088/1367-2630/14/4/043043
%0 Journal Article
%J Physical Review A
%D 2012
%T Growth of graph states in quantum networks
%A Cuquet, Martí
%A John Calsamiglia
%X We propose a scheme to distribute graph states over quantum networks in the presence of noise in the channels and in the operations. The protocol can be implemented efficiently for large graph sates of arbitrary (complex) topology. We benchmark our scheme with two protocols where each connected component is prepared in a node belonging to the component and subsequently distributed via quantum repeaters to the remaining connected nodes. We show that the fidelity of the generated graphs can be written as the partition function of a classical Ising-type Hamiltonian. We give exact expressions of the fidelity of the linear cluster and results for its decay rate in random graphs with arbitrary (uncorrelated) degree distributions.
%B Physical Review A
%V 86
%P 042304
%U http://link.aps.org/doi/10.1103/PhysRevA.86.042304
%R 10.1103/PhysRevA.86.042304
%0 Journal Article
%J {NATURE COMMUNICATIONS}
%D 0
%T {Generalized laws of thermodynamics in the presence of correlations}
%A Bera, Manabendra N.
%A Riera, Arnau
%A Lewenstein, Maciej
%A Winter, Andreas
%X {The laws of thermodynamics, despite their wide range of applicability, are known to break down when systems are correlated with their environments. Here we generalize thermodynamics to physical scenarios which allow presence of correlations, including those where strong correlations are present. We exploit the connection between information and physics, and introduce a consistent redefinition of heat dissipation by systematically accounting for the information flow from system to bath in terms of the conditional entropy. As a consequence, the formula for the Helmholtz free energy is accordingly modified. Such a remedy not only fixes the apparent violations of Landauer's erasure principle and the second law due to anomalous heat flows, but also leads to a generally valid reformulation of the laws of thermodynamics. In this information-theoretic approach, correlations between system and environment store work potential. Thus, in this view, the apparent anomalous heat flows are the refrigeration processes driven by such potentials.}
%B {NATURE COMMUNICATIONS}
%V {8}
%8 {DEC 19}
%R {10.1038/s41467-017-02370-x}