2004/01/31 by Simon Hands, David Walters, David N. Walters · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #hep-lat #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.69.076011
published as Phys.Rev. D69 (2004) 076011 · 41 pages, 19 figures, uses axodraw.sty, v2: minor typographical corrections
arxiv created 2004/04/01 · openalex publication_date 2004/04/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present results of numerical simulations of the (3+1)-dimensional Nambu--Jona-Lasinio model with a nonzero baryon density enforced via the introduction of a chemical potential \ensuremathμ\ensuremath≠0. The triviality of the model with a number of dimensions d>~4 is dealt with by fitting low energy constants, calculated analytically in the large number of colors (Hartree) limit, to phenomenological values. Nonperturbative measurements of local order parameters for superfluidity and their related susceptibilities show that, in contrast with the (2+1)-dimensional model, the ground state at high chemical potential and low temperature is that of a traditional BCS superfluid. This conclusion is supported by the direct observation of a gap in the dispersion relation for 0.5<~\ensuremathμa<~0.85, which at \ensuremathμa=0.8 is found to be roughly 15% the size of the vacuum fermion mass. We also present results of an initial investigation of the stability of the BCS phase against thermal fluctuations. Finally, we discuss the effect of splitting the Fermi surfaces of the pairing partners by the introduction of a nonzero isospin chemical potential.