Fine tuning

From Physical Review D: We investigate the initial conditions of inflation in a Bianchi I universe that is homogeneous but not isotropic. We use the Eisenhart lift to describe such a theory geometrically as geodesics on a field-space manifold. We construct the phase-space manifold of the theory by considering the tangent bundle of the field space and equipping it with a natural metric. We find that the total volume of this manifold is finite for a wide class of inflationary models. We therefore take the initial conditions to be uniformly distributed over it in accordance with Laplace’s principle of indifference. This results in a normalizable, reparametrization invariant measure on the set of initial conditions of inflation in a Bianchi I Read More ›