Momentum-dependent quasiparticle properties of the Fermi polaron from the functional renormalization group

Abstract

We study theoretically the lifetimes of attractive and repulsive Fermi polarons, as well as the molecule at finite momentum in three dimensions. To this end, we develop a new technique that allows for the computation of Green's functions in the whole complex frequency plane using exact analytical continuation within the functional renormalization group. The improved numerical stability and reduced computational cost of this method yield access to previously inaccessible momentum-dependent quasiparticle properties of low-lying excited states. While conventional approaches like the non-selfconsistent $T$-matrix approximation method cannot determine these lifetimes, we are able to find the momentum-dependent lifetime at different interaction strengths of both the attractive and repulsive polaron as well as the molecule. At weak coupling our results confirm predictions made from effective Fermi liquid theory regarding the decay of the attractive polaron, and we demonstrate that Fermi liquid-like behavior extends far into the strong-coupling regime where attractive polaron and molecule exhibit a $p^4$ momentum scaling in their decay widths. Our results offer an intriguing insight into the momentum-dependent quasiparticle properties of the Fermi polaron problem, which can be measured using techniques such as Raman transfer and Ramsey interferometry.

18 pages, 5 figures

References in corpus (35)

• Many-Body Physics with Ultracold Gases
• Exact evolution equation for the effective potential
• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
• The nonperturbative functional renormalization group and its applications
• Attractive and repulsive Fermi polarons in two dimensions
• Fermi-Polaron: Diagrammatic Monte Carlo for Divergent Sign-Alternating Series
• Repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms
• Normal state of a polarized Fermi gas at unitarity
• Strongly paired fermions: Cold atoms and neutron matter
• 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
• Trimers, molecules and polarons in imbalanced atomic Fermi gases
• Polaron-molecule transitions in a two-dimensional Fermi gas
• Highly polarized Fermi gases in two dimensions
• Ground state of a tightly bound composite dimer immersed in a Fermi Sea
• Polarons and Molecules in a Two-Dimensional Fermi Gas
• Renormalization Group Theory for the Imbalanced Fermi Gas
• Decay of polarons and molecules in a strongly polarized Fermi gas
• Mediated interactions between Fermi polarons and the role of impurity quantum statistics
• Collisional Properties of a Polarized Fermi Gas with Resonant Interactions
• Quasiparticle lifetime of the repulsive Fermi polaron
• Stability and breakdown of Fermi polarons in a strongly interacting Fermi-Bose mixture
• Quantum Monte Carlo Study of a Resonant Bose-Fermi Mixture
• Ground and Excited Exciton Polarons in Monolayer MoSe2
• Diagrammatic Monte Carlo study of quasi-two-dimensional Fermi-polarons
• Electron recoil effect in electrically tunable MoSe2 monolayers
• Renormalization group study of Bose polarons
• Condensed phase of Bose-Fermi mixtures with a pairing interaction
• Fermi polarons at finite temperature: Spectral function and rf-spectroscopy
• Realizing Topological Superconductivity in Tunable Bose-Fermi Mixtures with Transition Metal Dichalcogenide Heterostructures
• Thermodynamic signatures of the polaron-molecule transition in a Fermi gas
• Light-induced topological superconductivity in transition metal dichalcogenide monolayers
• Rabi oscillations and magnetization of a mobile spin-1/2 impurity in a Fermi sea
• The self-energy of an impurity in an ideal Fermi gas to second order in the interaction strength
• Spectral function of Fermi polarons at finite temperature from a self-consistent many-body $T$-matrix approach in real frequency

Cited by in corpus (3)

• Exact calculation of spectral properties of a particle interacting with a one-dimensional Fermi gas in optical lattices
• Functional renormalisation group approach to the finite-temperature Bose polaron
• Exact spectral properties of Fermi polarons in one-dimensional lattices: Anomalous Fermi singularities and polaron quasiparticles