Detection and dynamics of ultra-cold atoms in optical lattices

当原子冷却到非常低的温度时，它们的热运动几乎完全停止。利用激光和磁场捕获和冷却原子的方法的发展，为达到宇宙中已知的最低温度提供了工具。它们都在绝对零度的十亿分之一以内。在非常低的温度下，原子的波函数开始重叠，它们变得无法区分。玻色子原子经历玻色-爱因斯坦凝聚，代表了一种新的物质形式，玻色和爱因斯坦在近一个世纪前就预言了这一点。玻色-爱因斯坦凝聚体形成了类似于光学激光器的相干原子源；由此产生的原子激光器与普通原子光束的区别就像光学激光器与灯泡的区别一样。当玻色-爱因斯坦凝聚体被放置在由激光形成的周期性电位阵列（称为光学晶格）中时，它们的行为就像晶格中的电子一样。然而，与晶体晶格不同，光学晶格没有晶格缺陷，晶格高度和周期性可以很容易地设计。在光学晶格中，原子可以表现得像超导体中的电子，并且有可能成为下一代量子计算机的基石。期望的研究成果是利用光来观察、操纵和控制冷原子，进一步了解量子原子气体的基本知识，影响被困原子的实验进展。潜在的应用是精密测量，例如在卫星导航中使用原子钟改进时间测量的发展。

When atoms are cooled down to very low temperatures their thermal motion almost completely stops. The development of methods to trap and cool atoms be means of laser light and magnetic fields has provided tools to reach the lowest known temperatures in the Universe. These are within one billionth of a degree of absolute zero. At very cold temperatures the wave functions of the atoms start overlapping and they become indistinguishable. The bosonic atoms undergo the Bose-Einstein condensation, representing a new form of matter, predicted by Bose and Einstein almost a century ago. The Bose-Einstein condensates form a coherent source of atoms analogous to optical lasers; the resulting atom lasers are as different from ordinary atomic beams as optical lasers are from light bulbs. When the Bose-Einstein condensates are placed in periodic potential arrays formed by lasers, known as optical lattices, they behave like electrons in crystal lattices. However, unlike in crystal lattices, in optical lattices there are no lattice imperfections and the lattice height and the periodicity can be easily engineered. In optical lattices the atoms can behave like electrons in superconductors and could potentially be, e.g., the building block of a next generation quantum computer. The expected research outcomes are the means to observe, manipulate and control cold atoms by light, to further the basic understanding of quantum atomic gases and to influence the experimental progress with trapped atoms. The potential applications are in precision measurements, such as in the development of improved time measurements using atom clocks in satellite navigation.