Universal Loss Dynamics in a Unitary Bose Gas
Universal Loss Dynamics in a Unitary Bose Gas
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DOI：
10.1103/physrevx.6.021025
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发表时间：
2016-05-20
影响因子：
12.5
通讯作者：
Chin, Cheng
中科院分区：
文献类型：
--
作者：
Eismann, Ulrich;Khaykovich, Lev;Chin, Cheng
低温幺正玻色气体是少体和多体物理的基本范式，吸引了广泛的理论和实验兴趣。在这里，我们提出了在两种不同的设置中使用单一Cs-133和Li-7原子进行的实验，这使得能够定量比较低温域中的三体复合率。我们开发了一个理论模型，描述了两体蒸发和三体复合在一个谐波捕获的单一原子气体的冷凝温度以上的动态竞争。我们确定了一个通用的“魔术”陷阱深度，在某些参数范围内，蒸发冷却是平衡的复合加热和气体温度保持不变。我们的模型是为通常的三维蒸发制度以及二维蒸发的情况下，它完全支持我们的实验结果。结合Cs-133和Li-7的实验数据，可以调查损失动力学超过2个数量级的温度和4个数量级的三体损失率。我们证实了1/T-2温度普适定律。特别地，我们首次测量了Cs-133中47.8 G d波Feshbach共振的Efimov非弹性参数eta（*）= 0.098（7）。我们的结果支持了单一参数eta（*）下的囚禁幺正玻色气体的普遍损失动力学。
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 eta(*) = 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 eta(*).