Magnetic Instability in a Parity Invariant 2D Fermion System

TL;DR

This paper investigates magnetic instability in a parity-invariant 2D fermion system, showing it exists at low temperatures but vanishes at high temperatures, with implications for understanding ground state stability.

Contribution

It demonstrates the presence of magnetic instability in a parity-invariant 2D fermion system and analyzes its temperature dependence, which was not previously established.

Findings

Magnetic instability exists at low temperatures.

High temperature regime suppresses the magnetic instability.

Ground state becomes stable at high temperatures.

Abstract

We consider the parity invariant (2+1)-dimensional QED where the matter is represented as a mixture of fermions with opposite spins. It is argued that the perturbative ground state of the system is unstable with respect to the formation of magnetized ground state. Carrying out the finite temperature analysis we show that the magnetic instability disappears in the high temperature regime.