Critical fermion density for restoring spontaneously broken symmetry

TL;DR

This paper investigates how a high density of fermions can restore spontaneously broken symmetries across different physical systems, impacting particle physics, nuclear physics, and condensed matter.

Contribution

It introduces a critical fermion density threshold for symmetry restoration and discusses its implications in particle physics, nuclear physics, and superconductivity.

Findings

Critical fermion density for symmetry restoration calculated.

Implications for early universe processes in particle physics.

Potential effects on stellar core formation and collapse.

Abstract

We show how the phenomenon of spontaneous symmetry breakdown is affected by the presence of a sea of fermions in the system. When its density exceeds a critical value, the broken symmetry can be restored. We calculate the critical value and discuss the consequences for three different physical systems: First, for the standard model of particle physics, where the spontaneous symmetry breakdown leads nonzero masses of intermediate gauge bosons and fermions. The symmetry restoration will greatly enhance various processes with dramatic consequences for the early universe. Second, for the Gell-Mann--L\`evy $\sigma$-model of nuclear physics, where the symmetry breakdown gives rise to the nucleon and meson masses. The symmetry restoration may have important consequences for formation or collapse of stellar cores. Third, for the superconductive phase of condensed-matter, where the BCS condensate at low-temperature may be destroyed by a too large electron density.