  We study the order parameter of a quasi-2D gas of ultracold atoms trapped in
an optical potential in the presence of controllable disorder. Our results show
that disorder drives phase fluctuations without significantly affecting the
amplitude of the quasi-condensate order parameter. This is evidence that
disorder can drive phase fluctuations in 2D systems, relevant to the
phase-fluctuation mechanism for the superconductor-to-insulator phase
transition (SIT) in disordered 2D superconductors.
