The low-temperature unitary Bose gas is a fundamental paradigm in few-body and many-body physics, attracting wide theoretical and experimental interest. Here, we present experiments performed with unitary Cs 133 and Li 7 atoms in two different setups, which enable quantitative comparison of the three-body recombination rate in the low-temperature domain. We develop a theoretical model that describes the dynamic competition between two-body evaporation and three-body recombination in a harmonically trapped unitary atomic gas above the condensation temperature. We identify a universal “magic” trap depth where, within some parameter range, evaporative cooling is balanced by recombination heating and the gas temperature stays constant. Our model is developed for the usual three-dimensional evaporation regime as well as the two-dimensional evaporation case, and it fully supports our experimental findings. Combined Cs 133 and Li 7 experimental data allow investigations of loss dynamics over 2 orders of magnitude in temperature and 4 orders of magnitude in three-body loss rate. We confirm the 1 / T 2 temperature universality law. In particular, we measure, for the first time, the Efimov inelasticity parameter η * = 0.098 ( 7 ) for the 47.8-G d -wave Feshbach resonance in Cs 133 . Our result supports the universal loss dynamics of trapped unitary Bose gases up to a single parameter η * .
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机译：低温酉瓶气是少于身体和许多身体物理的基本范式，吸引了广泛的理论和实验兴趣。这里，我们在两种不同的设置中呈现用整体CS 133和Li 7原子进行的实验，这使得在低温域中的三体重组率的定量比较。我们开发了一种理论模型，描述了在冷凝温度高于谐振温度的双体蒸发和三体重组之间的动态竞争。我们识别通用的“魔法”陷阱深度，在某些参数范围内，通过重组加热和气体温度保持恒定的蒸发冷却。我们的模型是为通常的三维蒸发制度以及二维蒸发案件而开发的，它完全支持我们的实验结果。组合CS 133和Li 7实验数据允许在温度下的2个级和三个数量级以三体损失率调查损失动态。我们确认了1 / T 2温度普遍性法。特别是，我们首次测量EFIMOV绝形参数η* = 0.098（7），用于CS 133中的47.8g D -wave Feshbach谐振。我们的结果支持捕获的单一BOSE气体的通用损耗动态到单个参数η*。
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