We investigate the order of the finite temperature chiral symmetry restoration transition for QCD with two massless fermions, by using a novel method, based on simulating imaginary values of the quark chemical potential μ=iμi, μi∈ℝ. Our method exploits the fact that, for low enough quark mass m and large enough chemical potential μi, the chiral transition is decidedly first order, then turning into crossover at a critical mass mc(μ). It is thus possible to determine the critical line in the m−μ2 plane, which can be safely extrapolated to the chiral limit by taking advantage of the known tricritical indices governing its shape. We test this method with standard staggered fermions and the result of our simulations is that mc(μ=0) is positive, so that the phase transition at zero density is definitely first order in the chiral limit, on our coarse Nt=4 lattices with a≃0.3 fm.
Chiral phase transition in two-flavor QCD from an imaginary chemical potential
BONATI, CLAUDIO;D'ELIA, MASSIMO;
2014-01-01
Abstract
We investigate the order of the finite temperature chiral symmetry restoration transition for QCD with two massless fermions, by using a novel method, based on simulating imaginary values of the quark chemical potential μ=iμi, μi∈ℝ. Our method exploits the fact that, for low enough quark mass m and large enough chemical potential μi, the chiral transition is decidedly first order, then turning into crossover at a critical mass mc(μ). It is thus possible to determine the critical line in the m−μ2 plane, which can be safely extrapolated to the chiral limit by taking advantage of the known tricritical indices governing its shape. We test this method with standard staggered fermions and the result of our simulations is that mc(μ=0) is positive, so that the phase transition at zero density is definitely first order in the chiral limit, on our coarse Nt=4 lattices with a≃0.3 fm.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
