Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Nonequilibrium Quantum Many-Body Systems (joint session TT/DY)

TT 33.7: Talk

Thursday, September 8, 2022, 16:30–16:45, H22

Feynman-Vernon influence functional approach to quantum transport in interacting nanojunctions: An analytical hierarchical study — •Luca Magazzu and Milena Grifoni — University of Regensburg

We present a nonperturbative and formally-exact approach to the charge transport in interacting nanojunctions using a real-time path-integral method based on the Feynman-Vernon influence functional. Expansion of the influence functional in terms of the number of tunneling transitions results in an exact generalized master equation for the populations in the occupation-number representation, and in a formally exact expression for the current. We apply our method to the exactly solvable resonant level model (RLM) and to the single-impurity Anderson model (SIAM). For both systems, we demonstrate a hierarchical diagrammatic structure. While the hierarchy closes at the second tier for the RLM, this is not the case for the interacting SIAM. Upon inspection of the current kernel, known results from various perturbative and nonperturbative approximation schemes to quantum transport in the SIAM are recovered. Using a simplified fourth-tier scheme, analytical results for the interacting SIAM are presented both in equilibrium and nonequilibrium and with an applied magnetic field.

[1] L. Magazzù and M. Grifoni, Phys. Rev. B 105, 125417 (2022)