Speculations on an early geometrical phase transition: de Sitter–Gödel–de Sitter model

شیرین خدابخشی (دانشکده فیزیک دانشگاه تهران )

Abstract: De Sitter–Gödel–de Sitter (dGd) model is a possible geometrical phase transition from de Sitter to Gödel and back to de Sitter, controlled by a temperature dependent effective potential of a scalar field living on these backgrounds in early times. It is shown that due to a Casimir force in the Gödel phase, this phase transition could induce fluctuations on the matter and radiation fields with possibly observed traces. In this talk, After introducing the theoretical aspects and motivations of this model, a simulation of dGd-induced inhomogeneities and their power spectrum, parameterized by the parameter pair (p1, p2), as possible seeds of CMB anisotropies along with the standard inflationary perturbations will be presented. With the Planck 2018 observations, we find consistent results with pure inflationary power spectrum and no hint for the dGd transition. Future large scale surveys will be also considered to further tighten the constraints. Forecasts with the Euclid survey shows errors would improve by at least an order of magnitude compared to the constraints from CMB temperature and polarization anisotropies.

یکشنبه 27 بهمن 1398، ساعت 15:00

دانشکده فیزیک، طبقه چهارم تالار پرتوی