Use this URL to cite or link to this record in EThOS:
Title: The 3+1 dimensional lattice NJL model at non-zero baryon density
Author: Walters, D. N.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2003
Availability of Full Text:
Access from EThOS:
Lattice simulations of the 3+1 dimensional Nambu-Jona-Lasinio model have been undertaken that provide non-perturbative evidence for the existence of a BCS superfluid phase in the low temperature, high density regime. Standard analytic methods have been used to fit the model’s free parameters to low energy vacuum phenomenology. The model was simulated numerically for a range of baryon chemical potential m, with the introduction of a diquark source j to allow for the observation of spontaneous U(1) global symmetry breaking in a finite volume system. For m 0.6 and in the limit that j ® 0, a non-zero diquark condensate, a vanishing diquark susceptibility ratio and an energy gap D ≠ 0 about the Fermi surface in the fermion dispersion relation are all consistent with the ground-state being that of U(1)-broken BCS superfluid. The ratio between the gap at m = 0.8 and the vacuum fermion mass was found to be 0.15(2). This is interpreted as tentative non-perturbative evidence for the existence of a colour superconducting phase in cold, dense QCD. The effects of simulating on a finite volume, and any conditions this places on the above conclusions, were investigated. Finally, the results of some initial studies at non-zero isospin chemical potential and the prospect of simulations at non-zero temperature are discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available