We experimentally realize a method to produce nonequilibrium Bose-Einstein condensates with condensed fraction exceeding those of equilibrium samples with the same parameters. To do this, we immerse an ultracold Bose gas of ${}^{87}\mathrm{Rb}$ in a cloud of ${}^{39}\mathrm{K}$ with substantially higher temperatures, providing a controlled source of dissipation. By combining the action of the dissipative environment with evaporative cooling, we are able to progressively distil the nonequilibrium Bose-Einstein condensate from the thermal cloud. We show that by increasing the strength of the dissipation it is even possible to produce condensates above the critical temperature. We finally demonstrate that our out-of-equilibrium samples are long lived and do not reach equilibrium in a time that is accessible for our experiment. Due to its high degree of control, our distillation process is a promising tool for the engineering of open quantum systems.

中文翻译：

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超临界量子气体的耗散蒸馏。

我们通过实验实现了一种生产非平衡Bose-Einstein冷凝物的方法，该冷凝物的冷凝分数超过具有相同参数的平衡样品的冷凝分数。为此，我们将Bose超冷气体浸入${}^{87}b$ 在云中 ${}^{39}\mathrm{ķ}$具有明显更高的温度，提供了受控的耗散源。通过将耗散环境的作用与蒸发冷却相结合，我们能够逐步地从热云中蒸馏出非平衡的玻色-爱因斯坦冷凝物。我们表明，通过提高耗散强度，甚至可能会在临界温度以上产生冷凝水。最后，我们证明了失衡的样品寿命长，并且在我们的实验可以达到的时间内无法达到平衡。由于其高度的控制性，我们的蒸馏工艺是用于开放量子系统工程的有前途的工具。