Inflationary Universe with Anisotropic Hair
arXiv:0902.2833 · doi:10.1103/PhysRevLett.102.191302
Abstract
We study an inflationary scenario with a vector field coupled with an inflaton field and show that the inflationary universe is endowed with anisotropy for a wide range of coupling functions. This anisotropic inflation is a tracking solution where the energy density of the vector field follows that of the inflaton field irrespective of initial conditions. We find a universal relation between the anisotropy and a slow-roll parameter of inflation. Our finding has observational implications and gives a counter example to the cosmic no-hair conjecture.
10 pages, 2 figures; an error in abstract corrected; (v2) replaced with version accepted by PRL, title changed from "Hairy Inflation"
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