Magnetic susceptibility of QCD vacuum at finite density from the nonlocal chiral quark model

TL;DR

This paper investigates how the magnetic susceptibility of the QCD vacuum changes at finite density using a nonlocal chiral quark model, accounting for explicit flavor symmetry breaking due to nonzero quark masses.

Contribution

It introduces a detailed analysis of the magnetic susceptibility at finite density within a nonlocal chiral quark model, including effects of explicit quark mass.

Findings

Magnetic susceptibility decreases with nonzero quark mass.

Finite density reduces the magnetic response of the QCD vacuum.

Explicit flavor symmetry breaking impacts the susceptibility value.

Abstract

We present in this talk a recent investigation on the magnetic susceptibility (chi) of the QCD vacuum at finite density, utilizing the nonlocal chiral quark model from the instanton vacuum. We take into account the nonzero current-quark mass (m_q) explicitly to consider the effect of explicit flavor SU(3) symmetry breaking. It turns out that, when we turn on the current-quark mass, chi becomes smaller, indicating less response to the externally induced electromagnetic field, in comparison to that for m_q=0.