Quantum information approach to Bose-Einstein condensation of composite bosons

TL;DR

This paper explores how entanglement between constituent particles of composite bosons influences Bose-Einstein condensation, revealing contrasting behaviors for bi-fermions and bi-bosons in their effective ground state populations.

Contribution

It introduces a quantum information framework to analyze BEC of composite bosons, highlighting the role of entanglement in their condensation behavior.

Findings

Effective number of cobosons correlates with entanglement level.

Bi-fermions show increased ground state occupation with more entanglement.

Bi-bosons show decreased ground state occupation with more entanglement.

Abstract

We consider composite bosons (cobosons) comprised of two elementary particles, fermions or bosons, in an entangled state. First, we show that the effective number of cobosons implies the level of correlation between the two constituent particles. For the maximum level of correlation, the effective number of cobosons is the same as the total number of cobosons, which can exhibit the original Bose-Einstein condensation (BEC). In this context, we study a model of BEC for indistinguishable cobosons with a controllable parameter, i.e., entanglement between the two constituent particles. We find that bi-fermions behave in a predictable way, i.e., the effective number of the ground state coboson is an increasing function of entanglement between a pair of constituent fermions. Interestingly, bi-bosons exhibit the opposite behaviour - the effective number of the ground state coboson is a decreasing function of entanglement between a pair of constituent bosons.