Diagrammatic Monte Carlo study of mass-imbalanced Fermi-polaron system

Abstract

We apply the diagrammatic Monte Carlo approach to three-dimensional Fermi-polaron systems with mass-imbalance, where an impurity interacts resonantly with a noninteracting Fermi sea whose atoms have a different mass. This method allows to go beyond frequently used variational techniques by stochastically summing all relevant impurity Feynman diagrams up to a maximum expansion order limited by the sign problem. Polaron energy and quasiparticle residue can be accurately determined over a broad range of impurity masses. Furthermore, the spectral function of an imbalanced polaron demonstrates the stability of the quasiparticle and allows to locate in addition also the repulsive polaron as an excited state. The quantitative exactness of two-particle-hole wave-functions is investigated, resulting in a relative lowering of polaronic energies in the mass-imbalance phase diagram. Tan's contact coefficient for the mass-balanced polaron system is found in good agreement with variational methods. Mass-imbalanced systems can be studied experimentally by ultracold atom mixtures like ${}^6$Li-${}^{40}$K.

11 pages, 18 figures, replaced with published version

References in corpus (12)

• Many-Body Physics with Ultracold Gases
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• Normal state of highly polarized Fermi gases: Full many-body treatment
• Excitation spectra and rf-response near the polaron-to-molecule transition from the functional renormalization group
• Low-energy three-body dynamics in binary quantum gases
• Trimers, molecules and polarons in imbalanced atomic Fermi gases
• Highly polarized Fermi gases in two dimensions
• Ground state of a tightly bound composite dimer immersed in a Fermi Sea
• Bound states in a quasi-two-dimensional Fermi gas
• Diagrammatic Monte Carlo study of quasi-two-dimensional Fermi-polarons

Cited by in corpus (12)

• Heavy polarons in ultracold atomic Fermi superfluids at the BEC-BCS crossover: formalism and applications
• Polaron Problems in Ultracold Atoms: Role of a Fermi Sea across Different Spatial Dimensions and Quantum Fluctuations of a Bose Medium
• Exact quasiparticle properties of a heavy polaron in BCS Fermi superfluids
• High-precision numerical solution of the Fermi polaron problem and large-order behavior of its diagrammatic series
• Crossover polarons in a strongly interacting Fermi superfluid
• Fermi polarons at finite temperature: Spectral function and rf-spectroscopy
• Intersections of ultracold atomic polarons and nuclear clusters: How is a chart of nuclides modified in dilute neutron matter?
• Multidimensional Spectroscopy of Time-Dependent Impurities in Ultracold Fermions
• Boson-fermion pairing and condensation in two-dimensional Bose-Fermi mixtures
• Mass-gap description of heavy impurities in Fermi gases
• Spectral function of Fermi polarons at finite temperature from a self-consistent many-body $T$-matrix approach in real frequency
• The normal state of attractive Fermi gases from coupled-cluster theory