Momentum-resolved Raman spectroscopy of bound molecules in ultracold Fermi gas

TL;DR

This paper demonstrates a novel momentum-resolved Raman spectroscopy technique to measure binding energies and dispersion spectra of Feshbach molecules in ultracold Fermi gases, providing detailed insights into strongly interacting quantum gases.

Contribution

The study introduces a new experimental method for directly observing unpaired atoms and bound molecules simultaneously in ultracold Fermi gases using momentum-resolved Raman spectroscopy.

Findings

Direct measurement of binding energy of Feshbach molecules.

Reconstruction of energy-momentum dispersion spectra.

Potential for spatially and momentum-resolved spectroscopy in homogeneous systems.

Abstract

The binding energy of Feshbach molecules from a two component Fermi gas of $^{40}$K atoms has been experimentally measured with the momentum-resolved Raman spectroscopy. Comparing with the radio-frequency spectroscopy, in the present experiment the signal of unpaired (free atoms) and the bound molecules can be directly observed and the binding energy can be simultaneously determined in a single running experiment. The energy-momentum dispersion spectra of the strongly interacting ultracold Fermi gas in BEC side are also measured and reconstructed. The present experimental technology of the momentum-resolved Raman spectroscopy can be easily extended to perform spatially momentum-resolved Raman spectroscopy and to obtain the response spectra of a homogeneous system in the local density approximation.