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Nuclear Theory·nucl-th

Thursday·January 29, 2015

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 06

    [Submitted on 28 Jan 2015] (cross-list from quant-ph)

    Quantum decoherence in the entanglement entropy of a composite particle and its relationship to coarse graining in the Husimi function

    Yoshiko Kanada-En'yo

    I investigate quantum decoherence in a one-body density matrix of a composite particle consisting of two correlated particles. Because of a two-body correlation in the composite particle, quantum decoherence occurs in the one-body density matrix that has been reduced from the two-body density matrix. As the delocalization of the distribution of the composite particle grows, the entanglement entropy increases, and the system can be well-described by a semi-classical approximation, wherein the center position of the composite particle can be regarded as a classical coordinate. I connect the quantum decoherence in the one-body density matrix of a composite particle to the coarse graining in a phase space distribution function of a single particle and associate it with the Husimi function.

    Comments:
    4 pages, 1 figure
    Subjects:
    Quantum Physics (quant-ph); Strongly Correlated Electrons (cond-mat.str-el); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
    arXiv:
    1501.06991 [pdf]
    PTEP(2015)·9 citations
  2. 07

    [Submitted on 28 Jan 2015] (cross-list from quant-ph)

    On the question of current conservation for the Two-Body Dirac equations of constraint theory

    Matthias Lienert🇩🇪

    The Two-Body Dirac equations of constraint theory are of special interest not only in view of applications for phenomenological calculations of mesonic spectra but also because they avoid no-go theorems about relativistic interactions. Furthermore, they provide a quantum mechanical description in a manifestly Lorentz invariant way using the concept of a multi-time wave function. In this paper, we place them into the context of the multi-time formalism of Dirac, Tomonaga and Schwinger for the first time. A general physical and mathematical framework is outlined and the mechanism which permits relativistic interaction is identified. The main requirement derived from the general framework is the existence of conserved tensor currents with a positive component which can play the role of a probability density. We analyze this question for a general class of Two-Body Dirac equations thoroughly and comprehensively. While the free Dirac current is not conserved, it is possible to find replacements. Improving on previous research, we achieve definite conclusions whether restrictions of the function space or of the interaction terms can guarantee the positive definiteness of the currents -- and whether such restrictions are physically adequate. The consequences of the results are drawn, with respect to both applied and foundational perspectives.

    Comments:
    27 pages, no figures; v2: comparison with norm of Crater and Van Alstine and discussion of results on decay rates added
    Subjects:
    Quantum Physics (quant-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1501.07027 [pdf]
    J.Phys.A(2015)·10 citations
  3. 08

    [Submitted on 28 Jan 2015] (cross-list from hep-ph)

    The Tsallis Distribution at Large Transverse Momenta

    M.D. Azmi🇮🇳 · J. Cleymans🇿🇦

    Fits to the transverse momentum distributions of charged particles produced in p - p collisions at LHC energies based on the Tsallis distribution have been shown to work over 14 orders of magnitude. Two versions of the Tsallis distribution are compared and discussed, the thermodynamically consistent version leads to a temperature of T = 74 +/- 13 MeV at the highest beam energy, a result which is in agreement with previous analyses done with lower transverse momentum data.

    Comments:
    5 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1501.07127 [pdf]
    EPJC(2015)·73 citations

Affiliations

first authorsco-authorsvia INSPIRE