Mukhopadhyay, Annesh — Probing zero-momentum excitations in the stripe phase of a spin-orbit coupled Bose-Einstein condensate

Raman dressing of Bose-Einstein condensates is a highly flexible technique that pro- vides access to the study of interesting quantum phases. In a narrow range of parameters, an exotic supersolid-like stripe phase exists that combines superfluid properties with the breaking of translational symmetry. By using a weak optical lattice in combination with spin-orbit coupling, the parameter range for which such a state is the ground state of the system can be extended, which has led to the experimental realization of the state in our lab.

Here, we study this stripe phase by performing detuning quenches of the Raman dress- ing. We observe sinusoidal oscillations of the spin polarization after a quench, which gives us the corresponding zero-momentum excitation frequencies as a function of the optical lat- tice depth. This method of exciting quench dynamics is experimentally robust, providing a powerful tool for probing a predicted pseudo-Goldstone mode.