A mix of two bosonic particles develops attractive forces to create a quantum liquid A liquid exists when interactions that attract its constituent particles to each other are counterbalanced by a repulsion acting at higher densities. Other characteristics of liquids are short-range correlations and the existence of surface tension (1). Ultracold atom experiments provide a privileged platform with which to observe exotic states of matter, but the densities are far too low to obtain a conventional liquid because the atoms are too far apart to create repulsive forces arising from the Pauli exclusion principle of the atoms' internal electrons. The observation of quantum liquid droplets in an ultracold mixture of two quantum fluids is now reported on page 301 of this issue by Cabrera et al. (2) and a recent preprint by Semeghini et al. (3). Unlike conventional liquids, these liquids arise from a weak attraction and repulsive many-body correlations in the mixtures.

中文翻译：

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量子液体变薄

两种玻色子粒子的混合物会产生吸引力以产生量子液体 当将其组成粒子相互吸引的相互作用被以更高密度作用的排斥力抵消时，液体便存在。液体的其他特征是短程相关性和表面张力的存在 (1)。超冷原子实验提供了一个观察奇异物质状态的特权平台，但密度太低而无法获得常规液体，因为原子相距太远而无法产生由原子内部的泡利不相容原理引起的排斥力电子。Cabrera 等人在本期第 301 页报道了在两种量子流体的超冷混合物中观察到量子液滴。(2) 以及 Semeghini 等人最近的预印本。(3).