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Nuclear Theory·nucl-th

Friday·October 25, 2019

3 papers—1 primary·2 cross-listed

All3Primary1Cross-lists2
  1. 01

    Counting statistics in finite Fermi systems: illustrations with the atomic nucleus

    Denis Lacroix🇫🇷 · Sakir Ayik🇺🇸

    We analyze here in details the probability to find a given number of particles in a finite volume inside a normal or superfluid finite system. This probability, also known as counting statistics, is obtained using projection operator techniques directly linked to the characteristic function of the probability distribution. The method is illustrated in atomic nuclei. The nature of the particle number fluctuations from small to large volumes compared to the system size are carefully analyzed in three cases: normal systems, superfluid systems and superfluid systems with total particle number restoration. The transition from Poissonian distribution in the small volume limit to Gaussian fluctuations as the number of particles participating to the fluctuations increases, is analyzed both in the interior and at the surface of the system. While the restoration of total number of particles is not necessary for small volume, we show that it affects the counting statistics as soon as more than very few particles are involved.

    nucl-thcond-mat.quant-gascond-mat.str-elcond-mat.supr-conPRC(2020)·6 citations
  2. 02

    Dirac sea and chiral anomaly in the quantum kinetic theory

    Jian-Hua Gao🇨🇳 · Zuo-Tang Liang🇨🇳 · Qun Wang🇨🇳

    We revisit the chiral anomaly in the quantum kinetic theory in the Wigner function formalism under the background field approximation. Our results show that the chiral anomaly is actually from the Dirac sea or the vacuum contribution in the un-normal-ordered Wigner function. We also demonstrate that this contribution modifies the chiral kinetic equation for antiparticles.

    ↳ hep-phhep-thnucl-thPRD(2020)·29 citations
  3. 03

    Virtual Compton Scattering and Nucleon Generalized Polarizabilities

    H.Fonvieille (1) · B.Pasquini (2)(3) · N.Sparveris (4) · ((1) Université Clermont Auvergne, CNRS/IN2P3, LPC, F-63000 Clermont-Ferrand, France, (2) Dipartimento di Fisica Nucleare e Teorica, Universitá degli Studi di Pavia, (3) Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Italy, (4) Temple University, Philadelphia, PA 19122, USA)

    This review gives an update on virtual Compton scattering (VCS) off the nucleon, , in the low-energy regime. We recall the theoretical formalism related to the generalized polarizabilities (GPs) and model predictions for these observables. We present the GP extraction methods that are used in the experiments: the approach based on the low-energy theorem for VCS and the formalism of Dispersion Relations. We then review the experimental results, with a focus on the progress brought by recent experimental data on proton generalized polarizabilities, and we conclude by some perspectives in the field of VCS at low energy.

    ↳ nucl-exhep-phnucl-thPPNP(2020)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE