Ferromagnetism of quark liquid

TL;DR

This paper investigates the potential for ferromagnetism in quark liquids, proposing that low-density quark matter may spontaneously polarize due to one-gluon-exchange interactions, challenging the traditional view of non-polarized Fermi gas states.

Contribution

It introduces the idea that quark matter can exhibit spontaneous magnetic instability, similar to electron gas ferromagnetism, through a Hartree-Fock analysis with one-gluon-exchange.

Findings

Spontaneous magnetic instability occurs at low densities.

Polarized quark liquid can be metastable.

Challenges the assumption of non-polarized Fermi gas in quark matter.

Abstract

Usually it is believed that the Hartree-Fock state of quark matter is a Fermi gas state with no polarisation of spins. We examine the possibility of the polarised quark liquid interacting with the one-gluon-exchange interaction. It is suggested that the Hartree-Fock state shows a spontaneous magnetic instability at low densities through the same mechanism as the appearance of ferromagnetism in electron gas. Metastability of the polarised quark liquid is also discussed.