Quasi-instantons in QCD with chiral symmetry restoration

TL;DR

This paper demonstrates that in high-temperature QCD with restored chiral symmetry, the topological structure can be described as a Poisson ensemble of quasi-instantons, incorporating quantum effects without semiclassical approximations.

Contribution

It introduces the concept of quasi-instantons as quantum-corrected topological objects in high-temperature QCD, valid near the chiral phase transition.

Findings

Partition function expressed as a Poisson ensemble of quasi-instantons.

Quasi-instantons account for quantum effects in topological charge.

Applicable near the chiral phase transition temperature.

Abstract

We show, without using semiclassical approximations, that, in high-temperature QCD with chiral symmetry restoration and U(1) axial symmetry breaking, the partition function for sufficiently light quarks can be expressed as an ensemble of noninteracting objects with topological charge that obey the Poisson statistics. We argue that the topological objects are "quasi-instantons" (rather than bare instantons) taking into account quantum effects. Our result is valid even close to the (pseudo)critical temperature of the chiral phase transition.