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DOE OSTI · 1807937

Real-Frequency Response Functions at Finite Temperature

Tupitsyn, I S.·Tsvelik, Alexei M.·Konik, RM·Prokof'ev, NV
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Abstract

Building on previous developments [A. Taheridehkordi, S. H. Curnoe, and J. P. F. LeBlanc, Phys. Rev. B 99, 035120 (2019); A. Taheridehkordi, S. H. Curnoe, and J. P. F. LeBlancPhys. Rev. B101, 125109 (2020); A. Taheridehkordi, S. H. Curnoe, and J. P. F. LeBlancPhys. Rev. B102, 045115 (2020), B. Holm and U. von Barth, Phys. Rev. B 57, 2108 (1998), J. Vičičevic and M. Ferrero, Phys. Rev. B 101, 075113 (2020)], we show that the diagrammatic Monte Carlo technique allows us 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 us to study spectral densities of arbitrary complexity with controlled accuracy in models with frequency-dependent effective interactions. Finally, for illustrative purposes we consider the problem of the plasmon linewidth in a homogeneous electron gas (jellium).

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3-dimensional systems75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYFeynman diagramsMonte Carlo methodsdiagrammatic methodsdielectric propertiesfermionsfinite temperature field theorymany-body techniquesmetalsplasmonsquasiparticles & collective excitationsstrongly correlated systems

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Tupitsyn, I S., Tsvelik, Alexei M., Konik, RM, Prokof'ev, NV. 2021-07-09. Real-Frequency Response Functions at Finite Temperature. https://doi.org/10.1103/physrevlett.127.026403

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