We theoretically investigate the momentum-resolved radio-frequency spectroscopy of a harmonically trapped atomic Fermi gas near a Feshbach resonance in the presence of equal Rashba and Dresselhaus spin-orbit coupling. The system is qualitatively modeled as an ideal gas mixture of atoms and molecules, in which the properties of molecules, such as the wave function, binding energy, and effective mass, are determined from the two-particle solution of two interacting atoms. We calculate separately the radio-frequency response from atoms and molecules at finite temperatures by using the standard Fermi golden rule and take into account the effect of harmonic traps within local density approximation. The total radio-frequency spectroscopy is discussed as functions of temperature and spin-orbit coupling strength. Our results give a qualitative picture of radio-frequency spectroscopy of a resonantly interacting spin-orbit-coupled Fermi gas and can be directly tested in atomic Fermi gases of
40K atoms at Shanxi University and
6Li atoms at the Massachusetts Institute of Technology.
The authors prepare a quasi-two-dimensional spin-polarized Fermi gas with orbital excitations and p-wave interactions enabled by a Feshbach resonance. Radio-frequency spectroscopy indicates
s-wave scattering symmetry in the plane, demonstrating how gapped orbital degrees of freedom can be used to control scattering symmetry in strongly confined ultracold gases.
Spectroscopic measurements are made and obtained for three molecular levels within 50 MHz of the atomic continuum, along with their variation of magnetic field in ultracold 40 K Fermi gases. We use spectroscopic measurements to modify the scattering properties near magnetic Fano–Feshbach resonances with a radio-frequency (RF) field by measuring the loss profile versus magnetic field. This work provides the high accuracy locations of ground molecular states near the s-wave Fano–Feshbach resonance, which can be used to study the crossover regime from a Bose–Einstein condensate to a Bardeen–Cooper–Schrieffer superfluid in the presence of an RF field.