Radiofrequency spectroscopy of $^6$Li p-wave molecules: towards photoemission spectroscopy of a p-wave superfluid

TL;DR

This paper explores rf-spectroscopy of $^6$Li p-wave molecules near a Feshbach resonance to advance towards photoemission spectroscopy of p-wave superfluids, aiming to understand anisotropic superfluidity and its experimental signatures.

Contribution

It demonstrates rf-spectroscopy of p-wave molecules and proposes a method to observe anisotropic superfluid gaps in p-wave superfluids using optical lattices.

Findings

Confirmation of molecular and atomic spectral tunings with magnetic field

Evidence of bound molecule production via adiabatic ramps

Proposal for observing superfluid gaps in optical lattices

Abstract

Understanding superfluidity with higher order partial waves is crucial for the understanding of high-$T_c$ superconductivity. For the realization of a superfluid with anisotropic order parameter, spin-polarized fermionic lithium atoms with strong p-wave interaction are the most promising candidates to date. We apply rf-spectroscopy techniques that do not suffer from severe final-state effects \cite{Perali08} with the goal to perform photoemission spectroscopy on a strongly interacting p-wave Fermi gas similar to that recently applied for s-wave interactions \cite{Stewart08}. Radiofrequency spectra of both quasibound p-wave molecules and free atoms in the vicinity of the p-wave Feshbach resonance located at 159.15\,G \cite{Schunck05} are presented. The observed relative tunings of the molecular and atomic signals in the spectra with magnetic field confirm earlier measurements realized with direct rf-association \cite{Fuchs08}. Furthermore, evidence of bound molecule production using adiabatic ramps is shown. A scheme to observe anisotropic superfluid gaps, the most direct proof of p-wave superfluidity, with 1d-optical lattices is proposed.