On the quantum origin of the seeds of cosmic structure

I will briefly review the proposed mechanism of generation of inhomogeneities from quantum fluctuations during inflation. Then I will argue that that picture might not be complete and a new physical mechanism may be needed to accomplish the transition to inhomogeneity. I will give a phenomenological description of such a mechanism and speculate about the underlying physics. The work I report on was carried out in collaboration with A. Perez and D. Sudarsky.