Highly polarized one-dimensional Fermi gases near a narrow $p-$wave resonance

TL;DR

This paper investigates the properties of a single impurity in a highly polarized one-dimensional Fermi gas near a narrow p-wave resonance, revealing polaron and molecular states and their transition influenced by effective range.

Contribution

It introduces a variational approach considering effective range effects to analyze polaron and molecule states near a narrow p-wave resonance in 1D Fermi gases.

Findings

Polaron exhibits attractive and repulsive branches with varying scattering length.

Molecular state becomes energetically favorable at stronger interactions.

Polaron-to-molecule transition shifts towards the BCS side with increasing effective range.

Abstract

Based on the recently developed interaction renormalization for the one-dimensional $p$-wave interaction, we study the problem of a single impurity immersed in a highly polarized Fermi sea. They interact through a narrow $p$-wave Feshbach resonance, so the effective range $r_{0}$ naturally appears in the system. We use the variational approach limited to single-particle-hole excitations on top of the unperturbed Fermi sea. The polaron exhibits two branches of solutions, namely, the attractive and repulsive branches, with varying scattering length across the resonance. We calculate the energy spectrum, residue and effective mass for each of the branches. We compare the polaronic energy with the energy of the dressed molecule, and find that the molecular state is energetically favored when increasing the interaction strength. The critical interaction strength for the polaron-to-molecule transition will shift to the BCS side of the $p$-wave resonance as the effective range increases.