AI 中文总结
研究人员将弗洛凯理论融入非平衡格林函数形式主义，推导了与热库耦合的周期驱动量子系统的稳态量子统计解析表达式，建立了弗洛凯版朗道尔公式，为该类系统的相关研究提供了连贯描述。
AI 中文摘要
我们利用非平衡格林函数（NEGF）形式主义，推导了与热库耦合的周期驱动量子系统的稳态量子统计解析表达式。通过将弗洛凯理论嵌入NEGF，我们获得了弗洛凯表象下推迟、超前和 lesser 格林函数的闭式表达式，进而得到弗洛凯费米分布，其中稳态占据数表示为费米函数的加权和，这些费米函数由驱动频率的整数倍移位得到。权重仅由微运动算符的傅里叶分量确定，为弗洛凯边带占据提供了清晰的解释。我们的分析超越了早期工作中处理的对角对易哈密顿量，进一步表明，除了理想无特征热库近似外，鲁棒的弗洛凯分布对一大类弱耦合热库谱函数仍然有效。最后，我们建立了电流直流分量的弗洛凯版朗道尔公式，其中平衡费米函数被其弗洛凯修正对应物取代。这些结果共同为周期驱动开放量子系统中的弗洛凯量子统计和输运提供了连贯描述。
英文摘要
We derive an analytical expression for the steady-state quantum statistics of periodically driven quantum systems coupled to a bath using the nonequilibrium Green's function (NEGF) formalism. By embedding Floquet theory into NEGF, we obtain closed expressions for the retarded, advanced, and lesser Green's functions in the Floquet representation, yielding the Floquet Fermi distribution in which the steady-state occupation is expressed as a weighted sum of Fermi functions shifted by integer multiples of the driving frequency. The weights are determined solely by the Fourier components of the micromotion operator, providing a transparent interpretation of Floquet sideband occupations. Our analysis extends beyond the diagonal commuting Hamiltonians treated in earlier work, and further shows that the robust Floquet distribution remains valid for a broad class of weakly coupled bath spectral functions beyond the ideal featureless-bath approximation. Finally, we establish a Floquet version of the Landauer formula for the DC part of the current, in which the equilibrium Fermi functions are replaced by their Floquet-modified counterparts. Together, these results provide a coherent description of Floquet quantum statistics and transport in periodically driven open quantum systems.
Comments14 pages, 3 figures
