冷原子开放量子多体系统中非平衡态物理研究

Recently, lots of open quantum many-body systems have appeared in the fields of quantum optics, nanoscience, etc. The intrinsic nonequilibrium properties of these systems have dramatic influences on their various basic physical behavior. In particular, they could give rise to nonequilibrium dynamical scaling behavior on the macroscopic scale and phase transitions induced by the change of the nonequilibrium strength in these systems. This thus poses the urgent demand to understand the basic nonequilibrium physical behavior of these systems. In this project, by using nonequilibrium field theory techniques and numerical simulations of dynamical equations of the systems under study, we shall systematically investigate the following two aspects of nonequilibrium behaviors of driven-dissipative BECs and driven-dissipative degenerate Bose gases in optical lattices, both of which are of high relevance to current experiments on cold atom systems. (1) The influences of the number of components, the internal symmetry, and the range of interactions on the macroscopic nonequilibrium scaling behavior and scaling exponents of the driven-dissipative BECs. Are there new nonequilibrium dynamical universality classes in this type of systems? (2) Are there phase transitions in these systems that are induced by the change of nonequilibrium strengths? If so, what are the physical mechanisms that drive these transitions? These investigations will deepen our understanding of the basic nonequilibrium physical behavior of open quantum many-body systems and will also provide solid theoretical basis for on-going and further relevant experimental investigations.

近来量子光学,纳米科学等领域涌现出许多开放量子多体系统。这类系统的内禀非平衡态属性对其许多基本物理行为都有着重要的影响，并尤其体现在其中可能出现的宏观非平衡动力学标度行为和非平衡程度变化导致的相变。这对系统地理解其基本非平衡物理行为提出了迫切的需要。本项目以驱动-耗散型BEC和光晶格中驱动-耗散型简并玻色气体，这两类与当下冷原子实验联系紧密的冷原子开放量子多体系统为研究对象，围绕其内禀非平衡态属性，通过非平衡场论技术和对系统动力学方程大规模数值模拟，系统深入地研究：(1)驱动-耗散型BEC中，组份数目，内在对称性，相互作用力程，对其宏观非平衡动力学标度行为及指数的影响，从而探索可能出现的新非平衡动力学普适类；(2)这两类系统中非平衡程度变化可能诱发的相变及其物理驱动机制。该研究会加深对开放量子多体系统基本非平衡态物理行为的理解，并为国际上正兴起的相关实验研究提供坚实的理论基础。

近来量子光学,纳米科学等领域涌现出许多开放量子多体系统。这类系统的内禀非平衡态属性对其许多基本物理行为都有着重要的影响，并尤其体现在其中可能出现的宏观非平衡动力学标度行为和非平衡程度变化导致的相变。这对系统地理解其基本非平衡物理行为提出了迫切的需要。本项目以驱动-耗散型BEC和光晶格中驱动-耗散型简并玻色气体这两类与当下冷原子实验联系紧密的冷原子开放量子多体系统及其相关物理系统为研究对象，开展了广泛系统的研究，并侧重关注与系统内秉非平衡态属性相关的物理性质，发现了丰富的与传统平衡态物理系统区别显著的物理现象，相关研究加深了对开放量子多体系统基本非平衡态物理行为的理解，并为国际上正兴起的相关实验研究提供了理论基础。