Observation of Massless and Massive Collective Excitations with Faraday Patterns in a Two-Component Superfluid

We report on the experimental measurement of the dispersion relation of the density and spin collective excitation modes in an elongated two-component superfluid of ultracold bosonic atoms. Our parametric spectroscopic technique is based on the external modulation of the transverse confinement frequency, leading to the formation of density and spin Faraday waves. We show that the application of a coherent coupling between the two components reduces the phase symmetry and gives a finite mass to the spin modes.

Automated summary

We experimentally measured the dispersion relation of density and spin collective excitation modes in an elongated two-component superfluid of ultracold bosonic atoms. By utilizing a parametric spectroscopic technique based on external modulation of the transverse confinement frequency, we observed the formation of density and spin Faraday waves. Furthermore, we demonstrated that coherent coupling between the two components breaks the phase symmetry and imparts a finite mass to the spin modes.