Static correlation lengths in QCD at high temperature and finite density

TL;DR

This paper reviews the challenges of simulating finite density QCD, discusses an effective theory for the deconfined phase, and suggests potential for analytical continuation from imaginary to real chemical potential.

Contribution

It demonstrates that the dimensionally reduced effective theory can be efficiently simulated at finite chemical potential and explores the possibility of analytic continuation from imaginary to real chemical potential.

Findings

Effective theory simulation is feasible for $\mu/T\lsim 4$

Comparison indicates potential for analytic continuation

No current solution fully addresses the sign problem in realistic QCD

Abstract

A brief review is given of the sign problem in finite density lattice QCD and various attempts to overcome it. To date there is still no solution to this problem which would work for realistic QCD. The main focus then is on the deconfined phase, where QCD can be described by a dimensionally reduced effective action. After summarizing derivation and validity of the effective theory, it is demonstrated that it can be simulated efficiently in the presence of a chemical potential for quarks $\mu/T\lsim 4$. Direct comparison of simulations with imaginary and real $\mu$ suggests that equilibrium plasma properties could be analytically continued from 4d QCD simulations at imaginary $\mu$.