Inverse Monte-Carlo and Demon Methods for Effective Polyakov Loop Models of SU(N)-YM

Abstract

We study effective Polyakov loop models for SU(N) Yang-Mills theories at finite temperature. In particular effective models for SU(3) YM with an additional adjoint Polyakov loop potential are considered. The rich phase structure including a center and anti-center directed phase is reproduced with an effective model utilizing the inverse Monte-Carlo method. The demon method as a possibility to obtain the effective models' couplings is compared to the method of Schwinger-Dyson equations. Thermalization effects of microcanonical and canonical demon method are analyzed. Finally the elaborate canonical demon method is applied to the finite temperature SU(4) YM phase transition.

Finite volume phases of large-Ngauge theories with massive adjoint fermions

“…It is interesting to compare as well with the lattice phase diagram which results from adding a single double trace term to the pure gauge theory action [6,7]. The phase diagrams for these theories seem to suggest that the confined phase passes through (i.e., the strong and weak-coupling confined phases are connected) when the double trace term is strong enough.…”

“…In this paper we explore this possibility in adjoint QCD, that is, SU(N ) gauge theory with fermions in the adjoint representation. The phase diagram of this theory is quite rich when considering N f > 1 Majorana flavours with fermions of finite mass to which periodic boundary conditions have been applied in the temporal direction [6][7][8][9][10][11][12]. The intuition behind this is that the gauge field and fermion terms in the effective potential have opposite signs and compete to dominate the Polykov loop, with the fermions having a disordering effect.…”

Exotic phases of finite temperature gauge theories

“…Two important features of this phase diagram are that the confined phase is accessible in a region of weak coupling, and that there is a region of the parameter space in which a new, "skewed" phase is favoured over both the confined and deconfined phases. Both of these features were recently confirmed in [2] in simulations using a demon algorithm. Simulations of a similar theory in [3] also confirm that the confined phase becomes accessible beyond the deconfinement temperature of the pure gauge theory.…”

Asymptotic safety on the lattice: The nonlinear O(N) sigma model

“…Note that we have introduced an additional factor N in (19) in order to get rid of the leading N dependence of the couplings g. The couplings have mass dimension…”

“…Even worse, a standard method to determine the effective couplings relies on the matching of correlation functions on the initial and blocked lattices and requires expensive scanning runs for the parameters of the bare action at the largest lattice used [16]. In order to circumvent these problems we employ the demon method [17][18][19] which allows us to efficiently compute RG trajectories at a fixed lattice volume. In the present work we apply the MCRG method in combination with the demon method to calculate the global flow diagram of the ubiquitous nonlinear O(N) sigma models (NLSM) which are of interest both in condensed matter physics [20] and in particle physics [21].…”