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TT: Fachverband Tiefe Temperaturen

TT 29: Nonequilibrium Quantum Many-Body Systems 2 (joint session TT/DY)

TT 29.6: Vortrag

Dienstag, 17. März 2020, 15:15–15:30, HSZ 204

Mobility of the Fermi polaron for strong couplings — •Stefan Wittlinger¹, Lode Pollet¹, and Andrey Mishchenko² — ¹LMU Munich, Munich, Germany — ²RIKEN, Wako, Japan

We present an algorithmic scheme to calculate the mobility of the Fermi polaron, an impurity immersed into a Fermi bath, for strong couplings. In general, Monte Carlo simulations of the Fermi polaron problem suffer from the fermionic sign problem. For our scheme, we find a wide parameter range with a tractable sign problem. The perturbative expansion of the interaction is sampled using the diagrammatic determinantal quantum Monte Carlo algorithm. The sampling is done in imaginary time, which requires analytical continuation. Most theoretical treatments of the Fermi polaron problem only consider s-wave interactions or rely on the heavy particle approximation. Our scheme allows for the study of more realistic potentials by also considering higher order scattering terms. It also allows for the study of the problem without the heavy particle approximation. I will present results for a repulsive potential well for a wide range of masses and varying interaction ranges. Possible connections to the Anderson orthogonality catastrophe of the infinite mass case will also be discussed.