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arXiv · 2102.11418

Real-frequency response functions at finite temperature

I. S. Tupitsyn·A. M. Tsvelik·R. M. Konik·N. V. Prokof'ev
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Abstract

Building on previous developments, we show that the Diagrammatic Monte Carlo technique allows to compute finite temperature response functions directly on the real-frequency axis within any field-theoretical formulation of the interacting fermion problem. There are no limitations on the type and nature of the system's action or whether partial summation and self-consistent treatment of certain diagram classes are used. In particular, by eliminating the need for numerical analytic continuation from a Matsubara representation, our scheme allows to study spectral densities of arbitrary complexity with controlled accuracy in models with frequency-dependent effective interactions. For illustrative purposes we consider the problem of the plasmon line-width in a homogeneous electron gas (jellium).

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I. S. Tupitsyn, A. M. Tsvelik, R. M. Konik, N. V. Prokof'ev. 2021-07-16. Real-frequency response functions at finite temperature. https://doi.org/10.1103/physrevlett.127.026403

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