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arXiv · 2009.01061

A new form of liquid matter: quantum droplets

Zhihuan Luo·Wei Pang·Bin Liu·Yongyao Li·Boris A. Malomed
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Abstract

This brief review summarizes recent theoretical and experimental results which predict and establish the existence of quantum droplets (QDs), i.e., robust two- and three-dimensional (2D and 3D) self-trapped states in Bose-Einstein condensates (BECs), which are stabilized by effective selffirepulsion induced by quantum fluctuations around the mean-field (MF) states [alias the Lee-Huang--Yang (LHY) effect]. The basic models are presented, taking special care of the dimension crossover, 2D -> 3D. Recently reported experimental results, which exhibit stable 3D and quasi-2D QDs in binary BECs, with the inter-component attraction slightly exceeding the MF self-repulsion in each component, and in single-component condensates of atoms carrying permanent magnetic moments, are presented in some detail. The summary of theoretical results is focused, chiefly, on 3D and quasi-2D QDs with embedded vorticity, as the possibility to stabilize such states is a remarkable prediction. Stable vortex states are presented both for QDs in free space, and for singular but physically relevant 2D modes pulled to the center by the inverse-square potential, with the quantum collapse suppressed by the LHY effect.

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Zhihuan Luo, Wei Pang, Bin Liu, Yongyao Li, Boris A. Malomed. 2020-10-20. A new form of liquid matter: quantum droplets. https://arxiv.org/abs/2009.01061

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