Real-frequency response functions at finite temperature

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).

5 pages and 5 figures in the main text plus 7 pages and 7 figures in the Supplemental material

References in corpus (4)

• Numerical analytic continuation: Answers to well-posed questions
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• Decay dynamics of Localised Surface Plasmons: damping of coherences and populations of the oscillatory plasmon modes
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Cited by in corpus (8)

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• Renormalized Perturbation Theory for Fast Evaluation of Feynman Diagrams on the Real Frequency Axis
• One- and two-particle properties of the weakly interacting two-dimensional Hubbard model in proximity to the van Hove singularity
• Solving the Bethe-Salpeter Equation in Real Frequencies at Finite Temperature
• Physical and unphysical regimes of self-consistent many-body perturbation theory
• Automated evaluation of imaginary time strong coupling diagrams by sum-of-exponentials hybridization fitting