  We present a detailed analytical analysis of the propagation of Bogoliubov
phonons on top of Bose-Einstein condensates with spatial and temporal step-like
discontinuities in the hydrodynamic limit and focus on some features in the
correlations patterns, in particular of density-density correlations. The
application to the study of the Hawking signal in the formation of acoustic
black hole-like configurations is also discussed.

General Relativity and Quantum Cosmology;Quantum Gases;High Energy Physics - Theory