98 research outputs found

    Quantum entanglement dynamics and decoherence wave in spin chains at finite temperatures

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    We analyze the quantum entanglement at the equilibrium in a class of exactly solvable one-dimensional spin models at finite temperatures and identify a region where the quantum fluctuations determine the behavior of the system. We probe the response of the system in this region by studying the spin dynamics after projective measurement of one local spin which leads to the appearance of the ``decoherence wave''. We investigate time-dependent spin correlation functions, the entanglement dynamics, and the fidelity of the quantum information transfer after the measurement.Comment: Phys. Rev. A, accepted for publicatio

    QGP fireball explosion

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    We identify the major physics milestones in the development of strange hadrons as an observable for both the formation of quark-gluon plasma, and of the ensuing explosive disintegration of deconfined matter fireball formed in relativistic heavy ion collisions at 160--20A GeV. We describe the physical properties of QGP phase and show agreement with the expectations based on an analysis of hadron abundances. We than also demonstrate that the m_t shape of hadron spectra is in qualitative agreement with the sudden breakup of a supercooled QGP fireball.Comment: 10 pages, incl. 4 figures J. Phys. G in press; presented at STRANGENESS2000 International Conference, Berkeley July 200

    Effect of the unpolarized spin state in spin-correlation measurement of two protons produced in the 12C(d,2He) reaction

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    In this note we discuss the effect of the unpolarized state in the spin-correlation measurement of the 1S0^1S_0 two-proton state produced in 12C(d,2He) reaction at the KVI, Groningen. We show that in the presence of the unpolarized state the maximal violation of the CHSH-Bell inequality is lower than the classical limit if the purity of the state is less than ∌70% \sim \verb+70%+. In particular, for the KVI experiment the violation of the CHSH-Bell inequality should be corrected by a factor ∌10%\sim\verb+10%+ from the pure 1S0^1S_0 state.Comment: 6 pages, to appear in J. Phys.

    Quantum Preferred Frame: Does It Really Exist?

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    The idea of the preferred frame as a remedy for difficulties of the relativistic quantum mechanics in description of the non-local quantum phenomena was undertaken by such physicists as J. S. Bell and D. Bohm. The possibility of the existence of preferred frame was also seriously treated by P. A. M. Dirac. In this paper, we propose an Einstein-Podolsky-Rosen-type experiment for testing the possible existence of a quantum preferred frame. Our analysis suggests that to verify whether a preferred frame of reference in the quantum world exists it is enough to perform an EPR type experiment with pair of observers staying in the same inertial frame and with use of the massive EPR pair of spin one-half or spin one particles.Comment: 5 pp., 6 fig

    Extracting Classical Correlations from a Bipartite Quantum System

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    In this paper we discuss the problem of splitting the total correlations for a bipartite quantum state described by the Von Neumann mutual information into classical and quantum parts. We propose a measure of the classical correlations as the difference between the Von Neumann mutual information and the relative entropy of entanglement. We compare this measure with different measures proposed in the literature.Comment: 5 pages, 1 figur

    Distillable entanglement in d⊗dd\otimes d dimension

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    Distillable entanglement (EdE_d) is one of the acceptable measures of entanglement of mixed states. Based on discrimination through local operation and classical communication, this paper gives EdE_d for two classes of orthogonal multipartite maximally entangled states.Comment: 6 page

    Strangeness Content in the Nucleon

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    I review recent studies of strangeness content in the nucleon pertaining to the flavor-singlet gA0g_A^0, the sˉs\bar{s}s matrix element and the strangeness electric and magnetic form factors GEs(q2)G_E^s(q^2) and GMs(q2)G_M^s(q^2), based on lattice QCD calculations. I shall also discuss the relevance of incorporating the strangeness content in nuclei in regard to strange baryon-antibaryon productions from proton-nucleus and nucleus-nucleus collisions at SPS and RHIC energies.Comment: 11 pages, 4 figures, Invited talk at V Int. Conf. on Strangeness in Quark Matter, Berkeley, CA, July 20--25, 200

    System Size Dependence of Particle Production at the SPS

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    Recent results on the system size dependence of net-baryon and hyperon production as measured at the CERN SPS are discussed. The observed Npart dependences of yields, but also of dynamical properties, such as average transverse momenta, can be described in the context of the core corona approach. Other observables, such as antiproton yields and net-protons at forward rapidities, do not follow the predictions of this model. Possible implications for a search for a critical point in the QCD phase diagram are discussed. Event-by-event fluctuations of the relative core to corona source contributions might influence fluctuation observables (e.g. multiplicity fluctuations). The magnitude of this effect is investigated.Comment: 10 pages, 4 figurs. Proceedings of the 6th International Workshop on Critical Point and Onset of Deconfinement in Dubna, Aug. 201

    Overpopulation of Ωˉ\bar \Omega in pp collisions: a way to distinguish statistical hadronization from string dynamics

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    The Ωˉ/Ω\bar{\Omega}/\Omega ratio originating from string decays is predicted to be larger than unity in proton proton interactions at SPS energies (ElabE_{\rm lab}=160 GeV). The anti-omega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron production in proton proton collisions, it may serve as a key observable to probe the hadronization mechanism in such collisions.Comment: 4 pages, 4 figure

    Strange Particle Production at RHIC

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    We report STAR measurements of mid-rapidity yields for the Λ\Lambda, Λˉ\bar{\Lambda}, KS0K^{0}_{S}, Ξ−\Xi^{-}, Ξˉ+\bar{\Xi}^{+}, Ω−\Omega^{-}, and Ωˉ+\bar{\Omega}^{+} particles in Cu+Cu and Au+Au sNN=200\sqrt{s_{NN}} = 200 GeV collisions. We show that at a given number of participating nucleons, bulk strangeness production is higher in Cu+Cu collisions compared to Au+Au collisions at the same center of mass energy, counter to predictions from the Canonical formalism. We compare both the Cu+Cu and Au+Au yields to AMPT and EPOS predictions, and find they reproduce key qualitative aspects of the data. Finally, we investigate other scaling parameters and find bulk strangeness production for both the measured data and theoretical predictions, scales better with the number participants that undergo more than one collision.Comment: Conference proceedings for Hot Quarks 2008, 5 pages and 4 figure
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