Cold, dense matter via the lattice NJL model ∗

We simulate the lattice Nambu–Jona-Lasinio (NJL) model in 3+1-dimensions at non-zero baryon chemical potential (µ) and zero temperature (T) and treat the results as phenomenologically relevant for cold, dense quark matter. Measurements of the chiral condensate indicate a crossover in the thermodynamic limit, whilst at high chemical potential and zero temperature we observe a non-zero diquark condensate and a gap in the fermion dispersion relation, which together provide evidence for BCS superfluidity. In particular, the size of gap is found to be approximately 15% the value of the vacuum fermion mass and roughly independent of µ in the chirally restored phase.