Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion quadrupling state in two-component London models

TL;DR

This paper investigates how intercomponent couplings influence the emergence of a time-reversal symmetry breaking fermion quadrupling state in a two-component London model, using Monte Carlo simulations to explore phase behavior.

Contribution

It provides the first detailed analysis of the effects of intercomponent couplings on fermionic quadrupling states in two-component London models.

Findings

Identification of conditions favoring the fermion quadrupling state

Demonstration of phase transitions driven by intercomponent couplings

Insights into the role of couplings in symmetry breaking phenomena

Abstract

A detection of bosonic metallic state that breaks the $Z_2$ time-reversal symmetry has been recently reported in Ba$_{1-x}$K$_x$Fe$_2$As$_2$ with a doping level $x \approx 0.8$. This is a metallic state of fermionic quadruplets that breaks time-reversal symmetry. As such, it has no condensate of Cooper pairs but has a long-range order between fermionic quartets. In the present manuscript, we investigate the emergence of this phase in a two-component London model via Monte Carlo simulations as a function of various intercomponent couplings.