New DoS approaches to finite density lattice QCD

TL;DR

This paper introduces two novel density of states methods for finite density lattice QCD, utilizing the DoS FFA technique with different pseudo-fermion representations, validated through 2D test studies.

Contribution

It proposes two new DoS FFA-based approaches for finite density lattice QCD using distinct pseudo-fermion formulations, expanding the applicability of the method.

Findings

Successful implementation of two DoS FFA approaches for QCD

Validation against exact data in 2D free fermion tests

Potential for extending to more complex QCD systems

Abstract

We present two new suggestions for density of states (DoS) approaches to finite density lattice QCD. Both proposals are based on the recently developed and successfully tested DoS FFA technique, which is a DoS approach for bosonic systems with a complex action problem. The two different implementations of DoS FFA we suggest for QCD make use of different representations of finite density lattice QCD in terms of suitable pseudo-fermion path integrals. The first proposal is based on a pseudo-fermion representation of the grand canonical QCD partition sum, while the second is a formulation for the canonical ensemble. We work out the details of the two proposals and discuss the results of exploratory 2-d test studies for free fermions at finite density, where exact reference data allow one to verify the final results and intermediate steps.