Inflation — A window to Planck scale physics

The tremendous red-shifting of the perturbations during the inflationary epoch suggests that physics at the Planck scale may leave its imprints on the primordial spectrum and the cosmic microwave background. In the first part of the talk, I discuss the Planck scale corrections to the inflationary perturbation spectrum that arise in two different, locally Lorentz invariant, high-energy models. In the second part, I show that, given a modified spectrum, it can be reproduced with a suitably chosen squeezed state in the standard theory. I, therefore, argue that the primordial spectrum, by itself, may not be able to help us discriminate between the different Planck scale models of matter fields.