Mean-field theory and fluctuation spectrum of a pumped decaying Bose-Fermi system across the quantum condensation transition
Mean-field theory and fluctuation spectrum of a pumped decaying Bose-Fermi system across the quantum condensation transition
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DOI：
10.1103/physrevb.75.195331
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发表时间：
2006-11
影响因子：
3.7
通讯作者：
M. Szymańska;Jonathan Keeling;P. Littlewood
中科院分区：
文献类型：
--
作者：
M. Szymańska;Jonathan Keeling;P. Littlewood
本文研究了非平衡玻色-费米系统的平均场理论和量子涨落的性质。通过耦合到彼此不平衡的多个浴槽，使系统脱离平衡，并因此驱动颗粒通量通过系统。我们导出了均匀凝聚定态的自洽条件。这个条件可以与激光速率方程和平衡凝聚的Gross-Pitaevskii方程相比较。我们研究了稳定状态的波动，并讨论了多个浴如何相互作用，以设置系统的分布函数。在凝聚系统中，有一个软相（Bogoliubov，戈德斯通）模式，扩散在小动量由于存在的泵和衰变，我们讨论如何可以确定场场相关函数正确地包括这样的软相模式。在无限系统中，相关函数既不同于激光，也不同于平衡凝聚;我们讨论如何在有限系统中，激光极限可能会恢复。
We study the mean-field theory, and the properties of fluctuations, in an out of equilibrium Bose-Fermi system, across the transition to a quantum condensed phase. The system is driven out of equilibrium by coupling to multiple baths, which are not in equilibrium with each other, and thus drive a flux of particles through the system. We derive the self-consistency condition for a uniform condensed steady state. This condition can be compared both to the laser rate equation and to the Gross-Pitaevskii equation of an equilibrium condensate. We study fluctuations about the steady state and discuss how the multiple baths interact to set the system's distribution function. In the condensed system, there is a soft phase (Bogoliubov, Goldstone) mode, diffusive at small momenta due to the presence of pump and decay, and we discuss how one may determine the field-field correlation functions properly including such soft phase modes. In the infinite system, the correlation functions differ both from the laser and from an equilibrium condensate; we discuss how in a finite system, the laser limit may be recovered.