Phase structure of thermal lattice QCD withNf=2twisted mass Wilson fermions

Abstract

We present numerical results for the phase diagram of lattice QCD at finite temperature in the formulation with twisted mass Wilson fermions and a tree-level Symanzik-improved gauge action. Our simulations are performed on lattices with temporal extent N ¼ 8, and lattice coupling ranging from strong coupling to the scaling domain. Covering a wide range in the space spanned by the lattice coupling and the hopping and twisted mass parameters and , respectively, we obtain a comprehensive picture of the rich phase structure of the lattice theory. In particular, we verify the existence of an Aoki phase in the strong coupling region and the realization of the Sharpe-Singleton scenario at intermediate couplings. In the weak coupling region we identify the phase boundary for the physical finite temperature phase transition/crossover. Its shape in the three-dimensional parameter space is consistent with Creutz's conjecture of a cone-shaped thermal transition surface.

QCD propagators and vertices from lattice QCD (in memory of Michael Müller-Preußker)

“…During the first years, the tmfT Collaboration 1 focused on the phase structure in the temperature-mass plane, i.e., the three-dimensional parameter space for temperature, bare quark mass (hopping parameter) and twisted-mass parameter µ [11,12]. Of special interest were the thermal phase transition and the location of the Aoki phase [13].…”

On the phase structure of lattice QCD with twisted-mass Wilson fermions at non-zero temperature

“…Having included the twisted mass term a more complicated 3D phase diagram has to be explored. For lattice sizes N τ = 8, N σ = 16, we were able to show [11] that the Aoki phase ends somewhere inside the interval β = 3.0, . .…”

“…The results of this study supporting a conjecture for the phase diagram by M. Creutz from the chiral perturbation theory point of view [8,9] were already presented in Refs. [10,11]. Here we give an overview of the phase diagram but concentrating on the thermal transition surface.…”

Lattice QCD based on OpenCL

“…In our numerical studies [10][11][12] we employ the tree-level Symanzik improved Wilson action in the gauge sector,…”