Imaginary chemical potentials and the phase of the fermionic determinant

TL;DR

The paper introduces a numerical method to efficiently compute the average phase factor of the fermionic determinant at imaginary chemical potentials, validated in lattice QCD simulations with dynamical fermions.

Contribution

A novel numerical technique for calculating the phase factor of the fermionic determinant at imaginary chemical potentials, with validation and scaling analysis in lattice QCD.

Findings

Method successfully computes phase factor in QCD simulations.

Analytic continuation validity confirmed on small lattices.

Scaling behavior with lattice volume analyzed.

Abstract

A numerical technique is proposed for an efficient numerical determination of the average phase factor of the fermionic determinant continued to imaginary values of the chemical potential. The method is tested in QCD with eight flavors of dynamical staggered fermions. A direct check of the validity of analytic continuation is made on small lattices and a study of the scaling with the lattice volume is performed.