Isotropization of the universe during inflation

Thiago Pereira , Cyril Pitrou (1)

1 IAP - Institut d'Astrophysique de Paris

A primordial inflationary phase allows one to erase any possible anisotropic expansion thanks to the cosmic no-hair theorem. If there is no global anisotropic stress, then the anisotropic expansion rate tends to decrease. What are the observational consequences of a possible early anisotropic phase? We first review the dynamics of anisotropic universes and report analytic approximations. We then discuss the structure of dynamical equations for perturbations and the statistical properties of observables, as well as the implication of a primordial anisotropy on the quantization of these perturbations during inflation. Finally we review briefly models based on primordial vector field that evade the cosmic no-hair theorem.

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Mots clés: Cosmology; Inflation; Spatial anisotropy; Astrophysics - Cosmology and Nongalactic Astrophysics; General Relativity and Quantum Cosmology

Domaines: Planète et Univers [physics]

Thiago Pereira, Cyril Pitrou. Isotropization of the universe during inflation. Comptes Rendus. Physique, 2015, 16, pp.1027-1037. ⟨10.1016/j.crhy.2015.09.002⟩. ⟨insu-03644678⟩