Few body dynamics in the Bose–Einstein condensate

S. A. Sofianos, Tapan Kumar Das, Barnali Chakrabarti +3 more

Kaspar Sakmann

Bao Cheng-guang, Zhibing Li

S. Musolino, Hadrien Kurkjian, M. Van Regemortel +3 more

In an atomic Bose-Einstein condensate quenched to the unitary regime, we predict the sequential formation of a significant fraction of condensed pairs and triples. At short distances, we demonstrate the two-body and Efimovian character of the condensed pairs and triples, respectively. As the system evolves, their size becomes comparable to the interparticle distance, such that many-body effects become significant. The structure of the condensed triples depends on the size of Efimov states compared with density scales. Unexpectedly, we find universal condensed triples in the limit where these scales are well separated. Our findings provide a new framework for understanding dynamics in the unitary regime as the Bose-Einstein condensation of few-body composites.

Wu‐Ming Liu

Shohei Watabe

This paper discusses exact relations in the Bose-Einstein condensates, starting from basic properties of an ideal Bose gas.In particular, focused on are the Hugenholtz-Pines relation, Nepomnyashchii-Nepomnyashchii identity, and identities for the density response function.After introducing these exact relations, a few approaches of many-body approximations are discussed, which satisfy the exact relations in the Bose-Einstein condensates.This paper will serve as a bridge between theories on exact relations and those on approximations in the Bose-Einstein condensates.