Biexciton-like quartet condensates in an electron-hole liquid

TL;DR

This paper theoretically investigates the formation and properties of biexciton-like quartet condensates in an electron-hole liquid, revealing the persistence of four-body correlations at high densities using a BCS-like variational approach.

Contribution

It introduces a variational BCS model for quartet condensates in a four-component fermionic system, demonstrating the emergence and stability of biexciton-like correlations at high densities.

Findings

Cooper pairs and quartets appear in the equation of state.

Biexciton-like correlations persist at high densities.

Results enhance understanding of exotic quantum many-body states.

Abstract

We theoretically study the ground-state properties and the condensations of exciton-like Cooper pairs and biexciton-like Cooper quartets in an electron-hole system. Applying the variational approach associated based on the quartet Bardeen-Cooper-Schrieffer (BCS) model to the four-component fermionic system consisting of spin-1/2 electrons and spin-1/2 holes, we show how Cooper pairs and quartet correlations appear in the equation of state at the thermodynamic limit. The biexciton-like four-body correlations survive even at the high-density regime as a many-body BCS-like state of Cooper quartets. Our results are useful for further understanding of exotic matter in the interdisciplinary context of quantum many-body physics with multiple degrees of freedom.