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arXiv · 2312.05336

Beyond-mean-field effects in mixtures: few-body and many-body aspects

D. S. Petrov
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Abstract

The discovery of ultracold dilute liquids has significantly elevated our interest in various phenomena which go under the name of beyond-mean-field (BMF) physics. In these lecture notes we give an elementary introduction to the quantum stabilization and liquefaction of a collapsing weakly interacting Bose-Bose mixture. A detailed derivation of the leading BMF correction, also known as the Lee-Huang-Yang (LHY) term, in this system is presented in a manner suitable for further generalizations and extensions. Although the LHY term is a nonanalytic function of the density $n$, under certain conditions the leading BMF correction becomes analytic and can be expanded in integer powers of $n$, effectively introducing three-body and higher-order interactions. We discuss why and how well the Bogoliubov approach can predict these few-body observables.

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D. S. Petrov. 2023-12-08. Beyond-mean-field effects in mixtures: few-body and many-body aspects. https://arxiv.org/abs/2312.05336

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