Conveners
Nonzero Temperature and Density
- Francesco Di Renzo (INFN - National Institute for Nuclear Physics)
Nonzero Temperature and Density
- Wolfgang Unger (Universität Bielefeld)
It is important to investigate the sign problem around the phase transition region, where the sign problem is serious. We investigate the model sign problem in the Polyakov loop extended Nambu-Jona-Lasinio (PNJL) model with repulsive vector-type interaction at finite temperature and density by using the path optimization method [1]. The Polyakov loop and the repulsive vector-type interaction...
We study lattice QCD in the limit of infinite gauge coupling on a discrete spatial yet continuous Euclidean time lattice at finite baryon chemical potential $\mu_B$. The continuous time framework is based on sending $N_\tau\rightarrow \infty$ and the bare anisotropy to infinity while fixing the temperature in a non-perturbative setup. This leads to a sign problem free algorithm that allows us...
Lattice QCD with staggered fermions can be formulated in dual variables to address the finite baryon density sign problem. In the past we have performed simulations in the strong coupling regime, including leading order gauge corrections. In order to vary the temperature for fixed beta it was necessary to introduce a bare anisotropy. In this talk we will extend our work to include results from...
We improve our computation of canonical partition functions $Z_n$ in lattice QCD at high temperature using method of Fourier transformation at imaginary chemical potential. In particular, we explain the appearance of negative $Z_n$ and find the way to avoid their appearance. We also suggest another method to compute $Z_n$ at high temperature and demonstrate very good agreement between results...
The study of QFTs at finite density is hindered by the presence of the so-called sign problem. The action definition of such systems is, in fact, complex-valued making standard importance sampling Monte Carlo methods ineffective.
In this work, we shall review the generalized density of states method for complex action systems and the Linear Logarithmic Relaxation algorithm. We will focus on...
We explore the phase diagram of the 1+1 dimensional Gross-Neveu model at finite number of fermion flavors using lattice field theory. Besides a chirally symmetric phase and a homogeneously broken phase we find clear evidence for the existence of an inhomogeneous phase, where the chiral condensate is a spatially oscillating function. We present numerical results for the phase diagram and...
Lattice QCD in a dual formulation with staggered fermions is well established in the strong coupling limit and allows to perform Monte Carlo simulations at finite baryon chemical potential.
We have recently addressed the dependence of the nuclear critical end point as a function of the quark mass $m_q$ , and separately as a function of the inverse gauge coupling $\beta$ in the chiral...
We explore the possibility of a simulation of strong coupling QCD in terms of baryon bags. Since the gauge action is missing in the strong coupling partition sum, the integration over the gauge group is possible and the remaining Grassmann integral can be mapped to a statistical system of monomers, dimers and loops. Rather recently it was shown that the contributions from the baryons, i.e.,...
Combining strong coupling and hopping expansion one can derive a dimensionally reduced effective theory of lattice QCD.
This theory has a reduced sign problem, is amenable to analytic evaluation and was successfully used to study the cold and dense regime of QCD for sufficiently heavy quarks.
We show the derivation and evaluation of the effective theory for arbitrary $N_c$ up to...