Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany and Technische Universität Dresden, Institut für Theoretische Physik, 01187 Dresden, Germany.
Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany.
Phys Rev Lett. 2013 Dec 13;111(24):240405. doi: 10.1103/PhysRevLett.111.240405. Epub 2013 Dec 11.
Bose-Einstein condensation, the macroscopic occupation of a single quantum state, appears in equilibrium quantum statistical mechanics and persists also in the hydrodynamic regime close to equilibrium. Here we show that even when a degenerate Bose gas is driven into a steady state far from equilibrium, where the notion of a single-particle ground state becomes meaningless, Bose-Einstein condensation survives in a generalized form: the unambiguous selection of an odd number of states acquiring large occupations. Within mean-field theory we derive a criterion for when a single state and when multiple states are Bose selected in a noninteracting gas. We study the effect in several driven-dissipative model systems, and propose a quantum switch for heat conductivity based on shifting between one and three selected states.
玻色-爱因斯坦凝聚，即单个量子态的宏观占据，出现在平衡量子统计力学中，并且在接近平衡的流体力学状态下也能持续存在。在这里，我们表明，即使简并玻色气体被驱动进入远离平衡的稳态，其中单个粒子基态的概念变得毫无意义，玻色-爱因斯坦凝聚也以广义形式存在：明确选择获得大占据的奇数个状态。在平均场理论中，我们推导出了在非相互作用气体中，一个状态和多个状态被玻色选择的条件。我们研究了几个驱动耗散模型系统中的这种效应，并提出了一种基于在一个和三个选定状态之间切换的热导率量子开关。
