Simulating lattice QCD at finite temperature and zero quark mass

TL;DR

This paper uses lattice QCD simulations with an innovative approach to study the finite-temperature phase transition at zero quark mass, aiming to understand its universality class and critical behavior.

Contribution

It introduces a simulation method with an irrelevant chiral 4-fermion interaction to study the chiral phase transition at zero quark mass in lattice QCD.

Findings

Simulations on larger lattices aim to reveal continuum behavior.

Finite lattice-spacing artifacts influence the transition on coarse lattices.

Estimates of critical exponents for the phase transition.

Abstract

We simulate lattice QCD with an irrelevant chiral 4-fermion interaction which allows us to simulate at zero quark mass. This enables us to study the finite-temperature chiral-symmetry-restoring phase transition for 2 massless quark flavours, which is believed to be second order. In particular, it enables us to estimate the critical exponents which characterize the universality class of this transition. Our earlier simulations on $N_t=4$ and $N_t=6$ lattices revealed that finite lattice-spacing artifacts on such coarse lattices affect the nature of the transition. We are now simulating on $N_t=8$ lattices ($12^3 \times 8$, $16^3 \times 8$ and $24^3 \times 8$ lattices) where we expect to expose the continuum behaviour of this transition.