Bose-Einstein Condensation with Entangled Order Parameter

TL;DR

This paper introduces a new non-mean-field Bose-Einstein condensate state characterized by interspecies entanglement, leading to unique interference effects and broad experimental relevance.

Contribution

It presents a practically accessible entangled ground state of BEC with a novel entangled order parameter, expanding understanding beyond mean-field theories.

Findings

Entangled BEC state characterized by entanglement entropy

Persistent entanglement across a wide parameter range

Novel interference effects in dynamical equations

Abstract

We propose a practically accessible non-mean-field ground state of Bose-Einstein condensation (BEC), which occurs in an interspecies two-particle entangled state, and is thus described by an entangled order parameter. A suitably defined entanglement entropy is used as the characterization of the non-mean-field nature, and is found to persist in a wide parameter regime. The interspecies entanglement leads to novel interference terms in the dynamical equations governing the single particle orbital wavefunctions. Experimental feasibility and several methods of probe are discussed. We urge the study of multi-channel scattering between different species of atoms.