当一个复杂的系统被孤立时，它将以近乎完美的精度返回到初始状态。例如，一个容器中的气体颗粒在一段时间后将几乎完全返回它们的起始位置。几十年来，科学家们已经研究了这个“庞加莱回归定理（Poincaré recurrence theorem）”可以应用到量子物理的世界。现在，研究人员已经成功地展示了一种在多粒子量子系统中的“庞加莱回归”。

1. Bernhard Rauer, Sebastian Erne, Thomas Schweigler, Federica Cataldini, Mohammadamin Tajik, Jörg Schmiedmayer. Recurrences in an isolated quantum many-body system. Science, 2018; eaan7938 DOI: 10.1126/science.aan7938

见：

Vienna University of Technology. "Quantum recurrence: Everything goes back to the way it was: At some point, complex systems return almost exactly to their initial state. For the first time, this recurrence theorem has now been demonstrated with complex quantum many-body systems.." ScienceDaily. ScienceDaily, 22 February 2018.

https://www.sciencedaily.com/releases/2018/02/180222145053.htm