A signature of quantum gravity at the source of the seeds of cosmic structure?

Abstract

This article reviews a recent work by a couple of colleagues and myself [Perez A, Sahlmann H and Sudarsky D 2006 Class Quant Gravity 23 2317–54] about the shortcomings of the standard explanations of the quantum origins of cosmic structure in the inflationary scenario, and a proposal to address them. The point is that, in the usual accounts, the inhomogeneity and anisotropy of our universe seems to emerge from an exactly homogeneous and isotropic initial state through processes that do not break those symmetries. We argued that some novel aspect of physics must be called upon to be able to address the problem in a fully satisfactory way. The proposed approach is inspired by Penrose's ideas regarding a quantum gravity induced, real and dynamical collapse of the wave function.