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Nonequilibrium perturbation theory of the spinless Falicov-Kimball model

V. Turkowski·J. K. Freericks
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Abstract

We perform a perturbative analysis for the nonequilibrium Green functions of the spinless Falicov-Kimball model in the presence of an arbitrary external time-dependent but spatially uniform electric field. The conduction electron self-energy is found from a strictly truncated second-order perturbative expansion in the local electron-electron repulsion U. We examine the current at half-filling, and compare to both the semiclassical Boltzmann equation and exact numerical solutions for the contour-ordered Green functions from a transient-response formalism (in infinite dimensions) on the Kadanoff-Baym-Keldysh contour. We find a strictly truncated perturbation theory in the two-time formalism cannot reach the long-time limit of the steady state; instead it illustrates pathological behavior for times larger than approximately 2/U.

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V. Turkowski, J. K. Freericks. 2006-10-23. Nonequilibrium perturbation theory of the spinless Falicov-Kimball model. https://doi.org/10.1103/physrevb.75.125110

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