Induced magnetic moment in the magnetic catalysis of chiral symmetry breaking

TL;DR

This paper investigates how a magnetic field induces a magnetic moment in quark condensates, revealing new tensor channels and the coexistence of chiral and spin-one condensates, which enhance the critical temperature for symmetry restoration.

Contribution

It demonstrates the emergence of a spin-one condensate and a dynamical magnetic moment in magnetic catalysis, expanding understanding of chiral symmetry breaking mechanisms.

Findings

Magnetic field induces a spin-one condensate alongside the chiral condensate.

The new condensate acts as a dynamical magnetic moment affecting quasiparticle dispersion.

Critical temperature for chiral symmetry restoration is increased due to these effects.

Abstract

The chiral symmetry breaking in a Nambu-Jona-Lasinio effective model of quarks in the presence of a magnetic field is investigated. We show that new interaction tensor channels open up via Fierz identities due to the explicit breaking of the rotational symmetry by the magnetic field. We demonstrate that the magnetic catalysis of chiral symmetry breaking leads to the generation of two independent condensates, the conventional chiral condensate and a spin-one condensate. While the chiral condensate generates, as usual, a dynamical fermion mass, the new condensate enters as a dynamical anomalous magnetic moment in the dispersion of the quasiparticles. Since the pair, formed by a quark and an antiquark with opposite spins, possesses a resultant magnetic moment, an external magnetic field can align it giving rise to a net magnetic moment for the ground state. The two condensates contribute to the effective mass of the LLL quasiparticles in such a way that the critical temperature for chiral symmetry restoration becomes enhanced.