The Free Boundary Problem in GR

Abstract: A significant problem in physics and cosmology is the problem of initial/boundary conditions. This is both technical, as the boundary in these situations is typically a spacelike singularity (the Big Bang) and conceptual, as there is no clear way of choosing a set of initial condition without bias.

In this talk, I will present a general method for deducing initial conditions at the Big Bang, by treating the initial singularity as a free variational boundary. The resulting boundary conditions rule out Kasner-like geometries as well as BKL solutions, while favouring conformally regular geometries. In the case of linear perturbations around FLRW, the boundary conditions are equivalent to conformal regularity, in agreement with large-scale cosmological observations.

general relativity and quantum cosmologyHEP - experimentHEP - latticeHEP - phenomenologyHEP - theory

Audience: researchers in the topic

NKUA HEP Seminars

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