QCD quark condensate in external magnetic fields

TL;DR

This paper investigates how external magnetic fields influence light quark condensates in QCD across various temperatures, confirming magnetic catalysis at low temperatures and revealing complex behavior near the crossover.

Contribution

It provides a detailed lattice QCD analysis of light condensates with physical quark masses under magnetic fields, including continuum extrapolation and temperature dependence.

Findings

Magnetic catalysis confirmed at low temperatures.

Transition temperature decreases near the crossover.

Complex magnetic field dependence of condensates observed.

Abstract

We present a comprehensive analysis of the light condensates in QCD with 1+1+1 sea quark flavors (with mass-degenerate light quarks of different electric charges) at zero and nonzero temperatures of up to 190 MeV and external magnetic fields B<1 GeV^2/e. We employ stout smeared staggered fermions with physical quark masses and extrapolate the results to the continuum limit. At low temperatures we confirm the magnetic catalysis scenario predicted by many model calculations, while around the crossover the condensate develops a complex dependence on the external magnetic field, resulting in a decrease of the transition temperature.