84 research outputs found
Stochastic quantization at finite chemical potential
A nonperturbative lattice study of QCD at finite chemical potential is
complicated due to the complex fermion determinant and the sign problem. Here
we apply the method of stochastic quantization and complex Langevin dynamics to
this problem. We present results for U(1) and SU(3) one link models and QCD at
finite chemical potential using the hopping expansion. The phase of the
determinant is studied in detail. Even in the region where the sign problem is
severe, we find excellent agreement between the Langevin results and exact
expressions, if available. We give a partial understanding of this in terms of
classical flow diagrams and eigenvalues of the Fokker-Planck equation.Comment: 37 pages, many eps figures; references added, to appear in JHE
Simple QED- and QCD-like Models at Finite Density
In this paper we discuss one-dimensional models reproducing some features of
quantum electrodynamics and quantum chromodynamics at nonzero density and
temperature. Since a severe sign problem makes a numerical treatment of QED and
QCD at high density difficult, such models help to explore various effects
peculiar to the full theory. Studying them gives insights into the large
density behavior of the Polyakov loop by taking both bosonic and fermionic
degrees of freedom into account, although in one dimension only the
implementation of a global gauge symmetry is possible. For these models we
evaluate the respective partition functions and discuss several observables as
well as the Silver Blaze phenomenon.Comment: 5 pages, 2 figures. Final published versio
1/M correction to quenched QCD with non-zero baryon density
We study the \kappa^2 corrections to the quenched limit of \mu>0 QCD. We use
an improved reweighting procedure.Comment: Lattice2001(hightemp), 3 page
Complex Langevin: Boundary terms and application to QCD
We employ the Complex Langevin method for simulation of complex-valued
actions. First, we show how to test for convergence of the method by
explicitely computing boundary terms and demonstrate this in a model. Then we
investigate the deconfinement phase transition of QCD with
Wilson-fermions using the Complex Langevin Method and. We give preliminary
results for the transition temperatures up to and
compute the curvature coefficient .Comment: Proceedings for The 36th Annual International Symposium on Lattice
Field Theory - LATTICE2018; update: added some acknowledgement
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