Flavor number dependence of QCD at finite density by the complex Langevin method

TL;DR

This paper investigates how the number of quark flavors affects the applicability of the complex Langevin method in simulating QCD at high density and low temperature, providing insights into its validity across different flavor scenarios.

Contribution

It extends previous studies by analyzing flavor number dependence using Wilson fermions, identifying validity regions of the complex Langevin method for various flavor counts.

Findings

Validity regions depend on flavor number.

Complex Langevin method is applicable in certain density regimes.

Results support the method's use for more realistic flavor scenarios.

Abstract

We discuss the flavor number dependence of QCD at low temperature and high density by the complex Langevin method. In our previous work, the complex Langevin method is confirmed to satisfy the criterion for correct convergence in certain regions, such as $\mu_{\rm q} / T = 5.2-7.2$ on $8^3 \times 16$ and $\mu_{\rm q} / T = 1.6-9.6$ on $16^3 \times 32$ using $N_{\rm f} = 4$ staggered fermion at $\beta = 5.7$. We extend this study to more realistic flavor cases, $N_{\rm f} = 2, 2 + 1, 3$, using Wilson fermions. We present the flavor number dependence of the validity regions of the complex Langevin method and the quark number.