Bose-Einstein Condensation of Bound Pairs of Relativistic Fermions in a Magnetic Field

TL;DR

This paper investigates the effects of magnetic fields on the Bose-Einstein condensation of relativistic fermion pairs, revealing complex behaviors like magnetic catalysis and inverse magnetic catalysis influenced by coupling strength.

Contribution

It introduces a relativistic model that accounts for Gaussian fluctuations to analyze how magnetic fields affect bound pair condensation in different coupling regimes.

Findings

In weak coupling, magnetic field increases condensation temperature (magnetic catalysis).

In strong coupling, inverse magnetic catalysis occurs at low fields, switching to magnetic catalysis at high fields.

The response is driven by competition between Landau orbital effects and kinetic anisotropy.

Abstract

The Bose-Einstein condensation of bound pairs made of equally and oppositely charged fermions in a magnetic field is investigated using a relativistic model. The Gaussian fluctuations have been taken into account in order to study the spectrum of bound pairs in the strong coupling region. We found, in weak coupling reagion, the condensation temperature increases with an increasing magnetic field displaying the magnetic catalysis effect. In strong coupling region, the inverse magnetic catalysis appears when the magnetic field is low and is replaced by the usual magnetic catalysis effect when magnetic field is sufficiently high, in contrast to the nonrelativistic case where the inverse magnetic catalysis prevails in strong coupling region regardless of the strength of the magnetic field. The resulting response to the magnetic field is the consequence of the competition between the dimensional reduction by Landau orbitals in pairing dynamics and the anisotropy of the kinetic spectrum of the bound pairs. We thus conclude that dimensional reduction dominates in weak domain and strong coupling one except the small magnetic field region, where the enhanced fluctuations dominates.