TY  - JOUR
A1  - Brandt, Bastian Benjamin
A1  - Cuteri, Francesca
A1  - Endrődi, Gergely
A1  - Schmalzbauer, Sebastian
T1  - The Dirac spectrum and the BEC-BCS crossover in QCD at nonzero isospin asymmetry
T2  - Particles
N2  - For large isospin asymmetries, perturbation theory predicts the quantum chromodynamic (QCD) ground state to be a superfluid phase of u and d¯ Cooper pairs. This phase, which is denoted as the Bardeen-Cooper-Schrieffer (BCS) phase, is expected to be smoothly connected to the standard phase with Bose-Einstein condensation (BEC) of charged pions at μI≥mπ/2 by an analytic crossover. A first hint for the existence of the BCS phase, which is likely characterised by the presence of both deconfinement and charged pion condensation, comes from the lattice observation that the deconfinement crossover smoothly penetrates into the BEC phase. To further scrutinize the existence of the BCS phase, in this article we investigate the complex spectrum of the massive Dirac operator in 2+1-flavor QCD at nonzero temperature and isospin chemical potential. The spectral density near the origin is related to the BCS gap via a generalization of the Banks-Casher relation to the case of complex Dirac eigenvalues (derived for the zero-temperature, high-density limits of QCD at nonzero isospin chemical potential).
KW  - lattice QCD
KW  - isospin
KW  - BCS phase
Y1  - 2020
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/54447
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-544471
N1  - c 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
VL  - 3
IS  - 1
SP  - 80
EP  - 86
PB  - MDPI
CY  - Basel
ER  -