01074nas a2200157 4500008003900000022001400039245005600053210005600109300001100165490000700176520061900183100002200802700002200824700001800846856005200864 2012 d a1367-263000aBeyond pure state entanglement for atomic ensembles0 aBeyond pure state entanglement for atomic ensembles a0330340 v143 aWe analyze multipartite entanglement between atomic ensembles within quantum matter–light interfaces. In our proposal, a polarized light beam crosses sequentially several polarized atomic ensembles impinging on each of them at a given angle $\alpha$ i . These angles are crucial parameters for shaping the entanglement since they are directly connected to the appropriate combinations of the collective atomic spins that are squeezed. We exploit such a scheme to go beyond the pure state paradigm proposing realistic experimental settings to address multipartite mixed state entanglement in continuous variables.1 aStasińska, Julia1 aPaganelli, Simone1 aSanpera, Anna uhttp://stacks.iop.org/1367-2630/14/i=3/a=03303400411nas a2200109 4500008003900000245011500039210007000154300001100224490000700235100002200242856003700264 2012 d00aConvergence of expansions in Schrödinger and Dirac eigenfunctions, with an application to the R-matrix theory0 aConvergence of expansions in Schrödinger and Dirac eigenfunction a0221010 v531 aStasińska, Julia uhttp://arxiv.org/pdf/0912.2909v301384nas 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/1111.349401414nas a2200193 4500008003900000245007900039210006900118260003500187300001100222490000800233520071900241100002400960700002200984700002401006700002601030700002301056700001901079856012201098 2011 d00aBell Inequalities with No Quantum Violation and Unextendable Product Bases0 aBell Inequalities with No Quantum Violation and Unextendable Pro bAmerican Physical SocietycAug a0704010 v1073 aThe strength of classical correlations is subject to certain constraints, commonly known as Bell inequalities. Violation of these inequalities is the manifestation of nonlocality—displayed, in particular, by quantum mechanics, meaning that quantum mechanics can outperform classical physics at tasks associated with such Bell inequalities. Interestingly, however, there exist situations in which this is not the case. We associate an intriguing class of bound entangled states, constructed from unextendable product bases with a wide family of tasks, for which (i) quantum correlations do not outperform the classical ones but (ii) there exist supraquantum nonsignaling correlations that do provide an advantage.1 aAugusiak, Remigiusz1 aStasińska, Julia1 aHadley, Christopher1 aKorbicz, Jarosław, K1 aLewenstein, Maciej1 aAcín, Antonio uhttps://grupsderecerca.uab.cat/giq/publications/bell-inequalities-no-quantum-violation-and-unextendable-product-bases01755nas a2200265 4500008004100000245008100041210006900122260001700191300001500208490000700223520094900230653002701179653001601206653002301222653002801245653003001273653002501303653001901328100002201347700001801369700002201387700001801409700001301427856004901440 2009 eng d00aManipulating mesoscopic multipartite entanglement with atom-light interfaces0 aManipulating mesoscopic multipartite entanglement with atomlight bAPSc12/2009 a062304–80 v803 aEntanglementbetween two macroscopic atomic ensembles induced by measurement on anancillary light system has proven to be a powerful methodfor engineering quantum memories and quantum state transfer. Here weinvestigate the feasibility of such methods for generation, manipulation, anddetection of genuine multipartite entanglement (Greenberger-Horne-Zeilinger and clusterlike states) betweenmesoscopic atomic ensembles without the need of individual addressing ofthe samples. Our results extend in a nontrivial way theEinstein-Podolsky-Rosen entanglement between two macroscopic gas samples reported experimentally in[B. Julsgaard, A. Kozhekin, and E. Polzik, Nature (London) 413,400 (2001)]. We find that under realistic conditions, a secondorthogonal light pulse interacting with the atomic samples, can modifyand even reverse the entangling action of the first oneleaving the samples in a separable state. ©2009 The American Physical Society10aatom-photon collisions10aEPR paradox10ameasurement theory10amesoscopic entanglement10amultipartite entanglement10aquantum entanglement10aquantum optics1 aStasińska, Julia1 aRodó, Carles1 aPaganelli, Simone1 aSanpera, Anna1 aBirkl, G uhttp://link.aps.org/abstract/PRA/v80/e06230400455nas a2200133 4500008003900000245008500039210006900124260001200193300001100205490000700216100002400223700002200247856005200269 2009 d00aPositive maps, majorization, entropic inequalities and detection of entanglement0 aPositive maps majorization entropic inequalities and detection o c05/2009 a0530180 v111 aAugusiak, Remigiusz1 aStasińska, Julia uhttp://stacks.iop.org/1367-2630/11/i=5/a=053018