Towards a controlled study of the QCD critical point
arXiv:0807.0860 · doi:10.1088/0954-3899/35/10/104098
Abstract
The phase diagram of QCD, as a function of temperature T and quark chemical potential mu, may contain a critical point (mu_E,T_E) whose non-perturbative nature makes it a natural object of lattice studies. However, the sign problem prevents the application of standard Monte Carlo techniques at non-zero baryon density. We have been pursuing an approach free of the sign problem, where the chemical potential is taken as imaginary and the results are Taylor-expanded in mu/T about mu=0, then analytically continued to real mu. Within this approach we have determined the sensitivity of the critical chemical potential mu_E to the quark mass, d(μ_E)^2/dm_q|_{μ_E=0}. Our study indicates that the critical point moves to {\em smaller} chemical potential as the quark mass {\em increases}. This finding, contrary to common wisdom, implies that the deconfinement crossover, which takes place in QCD at mu=0 when the temperature is raised, will remain a crossover in the mu-region where our Taylor expansion can be trusted. If this result, obtained on a coarse lattice, is confirmed by simulations on finer lattices now in progress, then we predict that no {\em chiral} critical point will be found for mu_B \lesssim 500 MeV, unless the phase diagram contains additional transitions.
4 pages, 6 figures, proceedings of Quark Matter 2008, Jaipur (India), Feb. 2008, to appear in J. Phys. G
References in corpus (10)
- The order of the quantum chromodynamics transition predicted by the standard model of particle physics
- Critical point of QCD at finite T and μ, lattice results for physical quark masses
- The QCD phase diagram for small densities from imaginary chemical potential
- The Equation of State for Two Flavor QCD at Non-zero Chemical Potential
- The QCD Phase Diagram for Three Degenerate Flavors and Small Baryon Density
- The chiral critical line of N_f=2+1 QCD at zero and non-zero baryon density
- The Status of Lattice QCD at Finite Temperature
- Results on Finite Density QCD
- A QCD chiral critical point at small chemical potential: is it there or not?
- The 3-state Potts model as a heavy quark finite density laboratory