对量子系统相干性的研究和操控是当今物理学中最激动人心的进展之一。量子相干性不仅在一些基础的实验中起着重要的作用，同时还是许多新发展起来的量子技术的关键。本项目主要从以下几个方面开展研究工作：（1）针对在谐振子势和光晶格中的超冷原子气体，研究其不同量子多体态在TL干涉仪作用下的响应；（2）研究若干新奇冷原子系统的量子相干性特别是高阶关联函数在TL干涉仪下的演化；（3）重点研究量子临界区域系统量子相干性的普适规律。通过本项目的开展，可以检验和发展现有的相变理论，为实验开展相关研究打下基础。

The study and control of coherence in quantum systems is one of the most exciting recent developments in physics. Quantum coherence plays a crucial role in emerging quantum technologies as well as fundamental experiments. Using the Talbot-Lau (TL) interferometer as a tool, this project is aimed to study (1) the response of different many-body states of an ultracold atomic gas in a harmonic trap and/or an optical lattice to the TL interferometer; (2) the dynamics of the coherence properties, especially high order correlation functions, of several exotic ultracold atomic systems with the TL interferometer; (3)Special attention will be paid to the universal behavior of quantum coherence in the quantum critical regime. By this project, we can check and develop the present theory of phase transition, and lay foundations for experimental research.