Restoration of chiral symmetry in cold and dense Nambu--Jona-Lasinio model with tensor renormalization group

TL;DR

This paper investigates the chiral phase transition in the Nambu--Jona-Lasinio model at low temperature and high density using a novel tensor renormalization group method, revealing a first-order transition and providing equation of state data.

Contribution

It introduces a Grassmann tensor renormalization group approach to study the NJL model on the lattice at finite density, enabling analysis of chiral symmetry restoration.

Findings

First-order chiral phase transition observed at high density

Chiral condensate used as order parameter

Equation of state results presented

Abstract

We analyze the chiral phase transition of the Nambu--Jona-Lasinio model in the cold and dense region on the lattice developing the Grassmann version of the anisotropic tensor renormalization group algorithm. The model is formulated with the Kogut--Susskind fermion action. We use the chiral condensate as an order parameter to investigate the restoration of the chiral symmetry. The first-order chiral phase transition is clearly observed in the dense region at vanishing temperature with $\mu/T\sim O(10^3)$ on a large volume of $V=1024^4$. We also present the results for the equation of state.