Diagrammatic Monte Carlo study of the Fermi polaron in two dimensions

Understand

We study the properties of the two-dimensional Fermi polaron model in which an impurity attractively interacts with a Fermi sea of particles in the zero-range limit.

• We use a diagrammatic Monte Carlo (DiagMC) method which allows us to sample a Feynman diagrammatic series to very high order.
• The convergence properties of the series and the role of multiple particle-hole excitations are discussed.
• We study the polaron and molecule energy as a function of the coupling strength, revealing a transition from a polaron to a molecule in the ground state.