Vorberg Daniel, Wustmann Waltraut, Schomerus Henning, Ketzmerick Roland, Eckardt André
Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
Technische Universität Dresden, Institut für Theoretische Physik and Center for Dynamics, 01062 Dresden, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Dec;92(6):062119. doi: 10.1103/PhysRevE.92.062119. Epub 2015 Dec 9.
We investigate nonequilibrium steady states of driven-dissipative ideal quantum gases of both bosons and fermions. We focus on systems of sharp particle number that are driven out of equilibrium either by the coupling to several heat baths of different temperature or by time-periodic driving in combination with the coupling to a heat bath. Within the framework of (Floquet-)Born-Markov theory, several analytical and numerical methods are described in detail. This includes a mean-field theory in terms of occupation numbers, an augmented mean-field theory taking into account also nontrivial two-particle correlations, and quantum-jump-type Monte Carlo simulations. For the case of the ideal Fermi gas, these methods are applied to simple lattice models and the possibility of achieving exotic states via bath engineering is pointed out. The largest part of this work is devoted to bosonic quantum gases and the phenomenon of Bose selection, a nonequilibrium generalization of Bose condensation, where multiple single-particle states are selected to acquire a large occupation [Phys. Rev. Lett. 111, 240405 (2013)]. In this context, among others, we provide a theory for transitions where the set of selected states changes, describe an efficient algorithm for finding the set of selected states, investigate beyond-mean-field effects, and identify the dominant mechanisms for heat transport in the Bose-selected state.
我们研究了玻色子和费米子的驱动耗散理想量子气体的非平衡稳态。我们关注具有确定粒子数的系统，这些系统通过与几个不同温度的热库耦合或通过与热库耦合的同时进行时间周期驱动而被驱动至非平衡态。在（弗洛凯 - ）玻恩 - 马尔可夫理论框架内，详细描述了几种解析和数值方法。这包括基于占据数的平均场理论、考虑了非平凡两体关联的增强平均场理论以及量子跳跃型蒙特卡罗模拟。对于理想费米气体的情况，这些方法被应用于简单晶格模型，并指出了通过热库工程实现奇异态的可能性。这项工作的大部分致力于玻色子量子气体和玻色子选择现象，这是玻色 - 爱因斯坦凝聚的非平衡推广，其中多个单粒子态被选中以获得大量占据数[《物理评论快报》111, 240405 (2013)]。在此背景下，我们尤其提供了一个关于所选态集发生变化的跃迁理论，描述了一种用于找到所选态集的有效算法，研究了超出平均场的效应，并确定了玻色子选择态中热传输的主导机制。
