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Title: Collective modes and Kosterlitz-Thouless transition in a magnetic field in the planar Nambu–Jona-Lasinio model

It is known that a constant magnetic field is a strong catalyst of dynamical chiral symmetry breaking in 2+1 dimensions, leading to generating dynamical fermion mass even at weakest attraction. In this work we investigate the collective modes associated with the dynamical chiral symmetry breaking in a constant magnetic field in the (2+1)-dimensional Nambu–Jona-Lasinio model with continuous U(1) chiral symmetry. We introduce a self-consistent scheme to evaluate the propagators of the collective modes at the leading order in 1/N. The contributions from the vacuum and from the magnetic field are separated such that we can employ the well-established regularization scheme for the case of vanishing magnetic field. The same scheme can be applied to the study of the next-to-leading order correction in 1/N. We show that the sigma mode is always a lightly bound state with its mass being twice the dynamical fermion mass for arbitrary strength of the magnetic field. Since the dynamics of the collective modes is always 2+1 dimensional, the finite temperature transition should be of the Kosterlitz-Thouless (KT) type. We determine the KT transition temperature TKT as well as the mass melting temperature T* as a function of the magnetic field. It is found that themore » pseudogap domain TKT < T < T* is enlarged with increasing strength of the magnetic field. The influence of a chiral imbalance or axial chemical potential μ5 is also studied. We find that even a constant axial chemical potential μ5 can lead to inverse magnetic catalysis of the KT transition temperature in 2+1 dimensions. As a result, the inverse magnetic catalysis behavior is actually the de Haas–van Alphen oscillation induced by the interplay between the magnetic field and the Fermi surface.« less
 [1] ;  [2] ;  [1]
  1. Tsinghua Univ. and Collaborative Innovation Center of Quantum Matter, Beijing (China)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1550-7998; PRVDAQ
Grant/Contract Number:
11335005; 2013CB922000; 2014CB845400; AC52-06NA25396
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 90; Journal Issue: 5; Journal ID: ISSN 1550-7998
American Physical Society (APS)
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS dynamical chiral symmetry breaking; magnetic catalysis; Kosterlitz-Thouless transition; Nambu–Jona-Lasino model