We present a time-dependent formulation of coupled cluster theory. This theory allows for direct computation of the free energy of quantum systems at finite temperature by imaginary time integration and is closely related to the thermal cluster cumulant theory of Mukherjee and co-workers [ Chem. Phys. Lett. 1992, 192, 55−61; Phys. Rev. E 1993, 48, 3373−3389; Chem. Phys. Lett. 2001, 335, 281−288; Chem. Phys. Lett. 2002, 352, 63−69; Int. J. Mod. Phys. B 2003, 17, 5367−5377]. Our derivation of the finite-temperature theory highlights connections to perturbation theory and to zero-temperature coupled cluster theory. We show explicitly how the finite-temperature coupled cluster singles and doubles amplitude equations can be derived in analogy with the zero-temperature theory and how response properties can be efficiently computed using a variational Lagrangian. We discuss the implementation for realistic systems and showcase the potential utility of the method with calculations of the exchange correlation energy of the uniform electron gas under warm dense matter conditions.

中文翻译：

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有限温度下多Ferrion系统的耦合簇理论的时变表示

我们提出了时间依赖的耦合聚类理论。该理论允许通过虚部时间积分来直接计算有限温度下的量子系统的自由能，并且与Mukherjee及其同事的热簇累积量理论密切相关。物理 来吧 1992年，192，55-61; 物理 启ë 1993，48，3373-3389; 化学 物理 来吧 2001年，335，281-288; 化学 物理 来吧 2002年，352，63-69; 诠释 J.莫德。物理 乙 2003，17，5367-5377]。我们对有限温度理论的推论突出了与微扰理论和零温度耦合簇理论的联系。我们明确显示了如何与零温度理论类似地推导有限温度耦合的簇单双峰振幅方程，以及如何使用变分拉格朗日法有效地计算响应特性。我们讨论了现实系统的实现，并通过计算在热致密物质条件下均匀电子气的交换相关能，展示了该方法的潜在实用性。