High-precision numerical solution of the Fermi polaron problem and large-order behavior of its diagrammatic series

Abstract

The Fermi polaron is a quasiparticle that emerges when a mobile impurity is coupled to an ideal Fermi gas through a short-range interaction. Here, the authors introduce a simple Monte Carlo algorithm to compute its ground-state properties by evaluating the Feynman diagrammatic series. The fermionic sign does not cause any fundamental problem when going to high diagrammatic orders, and order $N$=30 is easily reached. Resummation of the divergent series through a conformal mapping yields the polaron energy with record accuracy.

Topics & Concepts