00586nas a2200109 4500008003900000245009000039210006900129260003100198100002800229700002000257856019900277 2020 d00aGeneral Mixed State Quantum Data Compression with and without Entanglement Assistance0 aGeneral Mixed State Quantum Data Compression with and without En aLos Angeles, CA, USAbIEEE1 aKhanian, Zahra, Baghali1 aWinter, Andreas uhttps://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=9166581https://ieeexplore.ieee.org/document/9174148/http://xplorestaging.ieee.org/ielx7/9166581/9173928/09174148.pdf?arnumber=917414800641nas a2200181 4500008003900000022001400039245003900053210003900092260001600131490000800147100001900155700002000174700001400194700002100208700002000229700002000249856019000269 2018 d a2469-992600aGaussian quantum resource theories0 aGaussian quantum resource theories cJan-08-20180 v9871 aLami, Ludovico1 aRegula, Bartosz1 aWang, Xin1 aNichols, Rosanna1 aWinter, Andreas1 aAdesso, Gerardo uhttps://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.98.02233500516nas a2200169 4500008003900000022001400039245006700053210006400120260001600184300001100200490000700211100001800218700002200236700002200258700001800280856004800298 2018 d a1751-811300aA generalized wave-particle duality relation for finite groups0 ageneralized waveparticle duality relation for finite groups cDec-10-2018 a4140150 v511 aBagan, Emilio1 aCalsamiglia, John1 aBergou, János, A1 aHillery, Mark uhttps://grupsderecerca.uab.cat/giq/node/91500483nas a2200145 4500008003900000022001400039245009100053210006900144260001600213300001100229490000700240100002400247700001800271856004800289 2018 d a0034-488500aGenuine quantum correlations in quantum many-body systems: a review of recent progress0 aGenuine quantum correlations in quantum manybody systems a revie cJan-07-2018 a0740020 v811 aDe Chiara, Gabriele1 aSanpera, Anna uhttps://grupsderecerca.uab.cat/giq/node/92100641nas a2200145 4500008003900000245007100039210006900110260001600179490000600195100002500201700001700226700002300243700002000266856020900286 2017 d00aGeneralized laws of thermodynamics in the presence of correlations0 aGeneralized laws of thermodynamics in the presence of correlatio cJan-12-20170 v81 aBera, Manabendra, N.1 aRiera, Arnau1 aLewenstein, Maciej1 aWinter, Andreas uhttp://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-x01323nas a2200169 4500008003900000022001400039245007000053210006900123260000800192490000700200520082300207100001901030700001801049700001901067700001901086856004801105 2017 d a0022-248800aGenuine-multipartite entanglement criteria based on positive maps0 aGenuinemultipartite entanglement criteria based on positive maps caug0 v583 aPositive 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.1 aClivaz, Fabien1 aHuber, Marcus1 aLami, Ludovico1 aMurta, Glaucia uhttps://grupsderecerca.uab.cat/giq/node/84601386nas a2200169 4500008003900000022001400039245006800053210006800121260000800189490000700197520087400204100002001078700002301098700002401121700002301145856004801168 2017 d a1367-263000aGlobal and local thermometry schemes in coupled quantum systems0 aGlobal and local thermometry schemes in coupled quantum systems coct0 v193 aWe 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.1 aCampbell, Steve1 aMehboudi, Mohammad1 aDe Chiara, Gabriele1 aPaternostro, Mauro uhttps://grupsderecerca.uab.cat/giq/node/84201474nas a2200169 4500008004100000245005300041210005100094300001100145490000700156520101500163100001301178700001601191700001301207700001501220700001601235856005301251 2015 eng d00aA geometric approach to quantum state separation0 ageometric approach to quantum state separation a1230150 v173 aProbabilistic 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.1 aBagan, E1 aYerokhin, V1 aShehu, A1 aFeldman, E1 aBergou, J A uhttp://stacks.iop.org/1367-2630/17/i=12/a=12301501511nas a2200205 4500008003900000022001400039245008600053210006900139260001200208300001600220490000800236520084300244100001301087700001301100700001501113700001801128700001501146700001701161856012701178 2014 d a1091-649000aGeneration and confirmation of a (100 x 100)-dimensional entangled quantum system0 aGeneration and confirmation of a 100 x 100dimensional entangled c04/2014 a6243 - 62470 v1113 aEntangled 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.1 aKrenn, M1 aHuber, M1 aFickler, R1 aLapkiewicz, R1 aRamelow, S1 aZeilinger, A uhttps://grupsderecerca.uab.cat/giq/publications/generation-and-confirmation-100-x-100-dimensional-entangled-quantum-system00504nas a2200157 4500008003900000022001400039245005300053210005200106260001100158300001100169490000800180100001900188700002100207700002000228856009800248 2014 d a1079-711400aGraph-Theoretic Approach to Quantum Correlations0 aGraphTheoretic Approach to Quantum Correlations c1/2014 a0404010 v1121 aCabello, Adán1 aSeverini, Simone1 aWinter, Andreas uhttps://grupsderecerca.uab.cat/giq/publications/graph-theoretic-approach-quantum-correlations00630nas a2200169 4500008003900000020002200039245007100061210006900132260007400201100002200275700002200297700002300319700002100342700002300363700002000386856005400406 2014 d a978-3-939897-73-600aGraph-theoretical Bounds on the Entangled Value of Non-local Games0 aGraphtheoretical Bounds on the Entangled Value of Nonlocal Games aDagstuhl, GermanybSchloss Dagstuhl–Leibniz-Zentrum fuer Informatik1 aChailloux, André1 aMančinska, Laura1 aScarpa, Giannicola1 aSeverini, Simone1 aFlammia, Steven, T1 aHarrow, Aram, W uhttp://drops.dagstuhl.de/opus/volltexte/2014/480701384nas a2200181 4500008003900000245006400039210006400103300001100167490000700178520086300185100002201048700002201070700002001092700001401112700001801126700002301144856003501167 2012 d00aGlass to superfluid transition in dirty bosons on a lattice0 aGlass to superfluid transition in dirty bosons on a lattice a0430430 v143 aWe 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.1 aStasińska, Julia1 aMassignan, Pietro1 aBishop, Michael1 aWehr, Jan1 aSanpera, Anna1 aLewenstein, Maciej uhttp://arxiv.org/abs/1111.349401119nas a2200133 4500008003900000245004700039210004700086300001100133490000700144520073800151100001900889700002200908856005500930 2012 d00aGrowth of graph states in quantum networks0 aGrowth of graph states in quantum networks a0423040 v863 aWe 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.1 aCuquet, Martí1 aCalsamiglia, John uhttp://link.aps.org/doi/10.1103/PhysRevA.86.04230401570nas a2200169 4500008003700000022001600037245007300053210006900126260001300195490000800208520105100216100002501267700001701292700002301309700002001332856004801352 0 d a{2041-1723}00a{Generalized laws of thermodynamics in the presence of correlations}0 aGeneralized laws of thermodynamics in the presence of correlatio c{DEC 19}0 v{8}3 a{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.}1 aBera, Manabendra, N.1 aRiera, Arnau1 aLewenstein, Maciej1 aWinter, Andreas uhttps://grupsderecerca.uab.cat/giq/node/926