String Theory seminar - Antonin Portelli  Seminar

Abstract: The recent work arXiv:1607.04878 showed that a holographic description of the early Universe allows one to obtain novel cosmological models, which are competitive with the more standard ΛCDM model to describe our Universe at early times. In this new model, the Cosmic Microwave Background (CMB) spectrum is related to the 2-point function of the trace of the energy-momentum tensor in the dual theory. The fit to Planck data suggests that the dual theory is a gauge theory coupled to scalar fields with a quartic interaction, which while perturbative at high momenta, it becomes non-perturbative at low momenta (low-multipole part of the CMB spectrum). Moreover, the dual theory suffers from severe infrared divergences in perturbation theory, which are believed to be only an artefact of perturbation theory. We propose to address both issues by computing the relevant 2-point functions in dual theory using fully non-perturbative lattice simulations.