Simultaneous fermion and exciton condensations from a model Hamiltonian

TL;DR

This paper introduces a model Hamiltonian that captures the simultaneous formation of fermion-pair (superconductivity) and exciton condensates, providing insights into their entanglement and potential realization in materials.

Contribution

The authors develop a generalized Hamiltonian that models dual fermion-exciton condensation, extending existing models for superconductivity and exciton condensation.

Findings

The Hamiltonian produces large-eigenvalue signatures of both condensates.

The dual-condensate wave function results from entanglement of fermion-pair and exciton wave functions.

The model offers insights into the forces needed to realize fermion-exciton condensates.

Abstract

Fermion-exciton condensation in which both fermion-pair (i.e., superconductivity) and exciton condensations occur simultaneously in a single coherent quantum state has recently been conjectured to exist. Here, we capture the fermion-exciton condensation through a model Hamiltonian that can recreate the physics of this new class of highly correlated condensation phenomena. We demonstrate that the Hamiltonian generates the large-eigenvalue signatures of fermion-pair and exciton condensations for a series of states with increasing particle numbers. The results confirm that the dual-condensate wave function arises from the entanglement of fermion-pair and exciton wave functions, which we previously predicted in the thermodynamic limit. This model Hamiltonian -- generalizing well-known model Hamiltonians for either superconductivity or exciton condensation -- can explore a wide variety of condensation behavior. It provides significant insights into the required forces for generating a fermion-exciton condensate, which will likely be invaluable for realizing such condensations in realistic materials with applications from superconductors to excitonic materials.