Finite-range effects in the two-dimensional repulsive Fermi polaron

We study the repulsive Fermi polaron in a two-component, two-dimensional system of fermionic atoms inspired by the results of a recent experiment with Yb-173 atoms [N. Darkwah Oppong et al., Phys. Rev. Lett. 122, 193604 (2019)]. We use the diffusion Monte Carlo method to report properties such as the polaron energy and the quasiparticle residue that have been measured in that experiment. To provide insight into the quasiparticle character of the problem, we also report results for the effective mass. We show that the effective range, together with the scattering length, is needed in order to reproduce the experimental results. Using different model potentials for the interaction between the Fermi sea and the impurity, we show that it is possible to establish a regime of universality, in terms of these two parameters, that includes the whole experimental regime. This illustrates the relevance of quantum fluctuations and beyond mean-field effects to correctly describe the Fermi polaron problem.

Automated summary

This study focuses on the repulsive Fermi polaron in a two-component, two-dimensional system of fermionic atoms, investigating properties such as polaron energy, quasiparticle residue, and effective mass using the diffusion Monte Carlo method. The results highlight the importance of considering the effective range and scattering length to reproduce experimental results, as well as the establishment of universality through different model potentials for the interaction between the Fermi sea and the impurity. This underscores the significance of quantum fluctuations and beyond mean-field effects in accurately describing the Fermi polaron problem.