Theory of ultracold atoms: from fundamentals of quantum mechanics to applications

激光冷却等技术现在可以将原子气体冷却到比绝对零度高几十亿分之一度的温度。这些“超冷”原子的行为方式是非常量子力学的，因为它们的德布罗意波长非常大(~微米，即比室温下大5个数量级)。超冷原子已经被用来制造新的物质状态，比如玻色-爱因斯坦凝聚(BEC)，在这种凝聚中，气体中的每个原子都有相同的量子波函数。然而，超冷原子的科学潜力不仅限于基本的量子力学；它们的运动状态可以控制到前所未有的程度，以至于它们也开始在精确测量自然力和常数方面发挥重要作用。我的研究涉及到这两个方面背后的理论。

Techniques such as laser cooling can now cool gases of atoms to temperatures as low as a few billionths of one degree above absolute zero (nK). These "ultracold" atoms behave in a very quantum mechanical way because their de Broglie wavelengths are so large (~µm, i.e., 5 orders of magnitude larger than at room temperature). Ultracold atoms have already been used to make new states of matter such as Bose-Einstein condensates (BECs) in which every atom in the gas has the same quantum wave function. However, the scientific potential of ultracold atoms is not just confined to fundamental quantum mechanics; their motional state can be controlled to such an unprecedented degree that they are also beginning to play an important role in precision measurements of nature's forces and constants. My research concerns the theory behind both of these aspects.