  We theoretically analyze interference patterns of parametrically driven one
dimensional ultracold atomic gases. By modulating the interaction strength
periodically in time, we propose to excite collective modes in a pair of
independent one dimensional gases at energies corresponding to the drive
frequency. The excited collective modes lead to spatial oscillations in the
correlations of the interference pattern, which can be analyzed to obtain the
sound velocity of the collective modes. We discuss both bosonic and fermionic
systems, and how such experiments could be used to probe spin charge
separation.
