Testing dynamical stabilization of Complex Langevin simulations of QCD

TL;DR

This paper investigates the use of a dynamical stabilization term in complex Langevin simulations of QCD, demonstrating its effectiveness at low temperatures and proposing a method to correct biases introduced by the stabilization.

Contribution

It introduces and evaluates a dynamical stabilization technique for complex Langevin simulations of QCD, including a bias correction method via extrapolation.

Findings

DS term stabilizes simulations at low temperatures

Extrapolation can remove bias from stabilization

High temperatures do not require stabilization

Abstract

We study complex Langevin simulations of a toy model as well as QCD, supplemented with a dynamical stabilization (DS) term, which was proposed to regularize the complexified process at lower temperatures. We compare the results to reweghting from zero chemical potential to measure the bias that the inclusion of the stabilization term causes, depending on its strength. At high temperatures the stabilization term is not needed. At low temperatures (below deconfinement transition) the DS term has a beneficial stabilizing effect, but too strong DS term causes phase quenching on the system. We observed that the bias of the dynamical stabilization can be to a good accuracy removed by extrapolating to zero dynamical stabilization force using a sigmoid fit.