Date and Time: Friday, 2 pm, June 10, 2022
Exploring the quantum nature of cosmological perturbations
Krishna Mohan Parattu
We believe there was a period of exponential expansion, called inflation, in the evolutionary history of the universe. Brought on to solve some puzzles in the standard big bang cosmology, inflation also provides a mechanism of origin for the large-scale structure that we see in the universe as the distribution of galaxies and galaxy clusters, and also the temperature variations in the cosmic microwave background. According to this picture, these structures were seeded by quantum fluctuations of the scalar field driving inflation and then stretched out to cosmological scales by the inflationary expansion. Within this paradigm, one may ask why these fluctuations appear largely classical. On the other hand, one may ask if there are any remnant quantum features to prove that these fluctuations indeed had a quantum origin. I will discuss these issues and present results in the case of some models of current interest in the community for their ability to produce primordial black holes.