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Nuclear Theory·nucl-th

Monday·May 18, 2015

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 14 May 2015]

    Pomeranchuk instability and Bose condensation of scalar quanta in a Fermi liquid

    E. E. Kolomeitsev🇸🇰 · D. N. Voskresensky🇷🇺

    We study excitations in a normal Fermi liquid with a local scalar interaction. Spectrum of bosonic scalar-mode excitations is investigated for various values and momentum dependence of the scalar Landau parameter in the particle-hole channel. For the conditions are found when the phase velocity on the spectrum of the zero sound acquires a minimum at a non-zero momentum. For there are only damped excitations, and for the spectrum becomes unstable against a growth of scalar-mode excitations (a Pomeranchuk instability). An effective Lagrangian for the scalar excitation modes is derived after performing a bosonization procedure. We demonstrate that the Pomeranchuk instability may be tamed by the formation of a static Bose condensate of the scalar modes. The condensation may occur in a homogeneous or inhomogeneous state relying on the momentum dependence of the scalar Landau parameter. Then we consider a possibility of the condensation of the zero-sound-like excitations in a state with a non-zero momentum in Fermi liquids moving with overcritical velocities, provided an appropriate momentum dependence of the Landau parameter .

    Comments:
    12 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
    arXiv:
    1505.03884 [pdf]
    1 citation
  2. 02

    [Submitted on 15 May 2015]

    Structures in 9Be, 10Be and 10B studied with tensor-optimized shell model

    Takayuki Myo · Atsushi Umeya · Hiroshi Toki · Kiyomi Ikeda

    We investigate the structures of Be and B with the tensor-optimized shell model (TOSM) using the effective interaction based on the bare nucleon-nucleon interaction AV8. The tensor correlation is treated in TOSM with the full optimization of 2p2h configurations including high-momentum components. The short-range correlation is described in the unitary correlation operator method (UCOM). It is found that the level orders of the low-lying states of Be and B are entirely reproduced. For Be, ground band states are located relatively in higher energy than the experiments, which indicates the missing clustering correlation in these states as seen in the case of Be with TOSM. In addition, the tensor force gives the larger attraction for =1/2 states than for =3/2 ones for Be. For Be, the tensor contribution of shows the largest value among the states. This can be related to the clustering correlation in this state. It is also found that the level order of three nuclei depends on the tensor force in comparison with the results obtained with the Minnesota interaction without the tensor force.

    Comments:
    12 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1505.03942 [pdf]
    PTEP(2015)·8 citations
  3. 03

    [Submitted on 15 May 2015]

    New Theoretical Results on Event-by-Event Fluctuations

    Mark I. Gorenstein🇺🇦

    Several theoretical results concerning event-by-event fluctuations are discussed: (1) a role of the global conservation laws and concept of statistical ensembles; (2) strongly intensive measures are introduced; they give a possibility to study e-by-e fluctuations for physical systems with volume fluctuations; (3) identity method for chemical fluctuations in a case of incomplete particle identification; (4) the example of particle number fluctuations in a vicinity of the critical point.

    Comments:
    invited talk at the CPOD 2014 conference, 25 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1505.04135 [pdf]
    PoS(2015)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE