arXiv 0806.03772008-06astro-ph

A Hemispherical Power Asymmetry from Inflation

Adrienne L. Erickcek, Marc Kamionkowski, Sean M. Carroll

备注：: 5 pages, 2 figures; v3 reformatted with minor corrections made and refs. added; to appear in PRD
发表信息：: Phys.Rev.D78:123520,2008
DOI：: 10.1103/PhysRevD.78.123520

英文摘要：

Measurements of CMB temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry cannot be generated during single-field slow-roll inflation without violating constraints to the homogeneity of the Universe. In contrast, a multi-field inflationary theory, the curvaton model, can produce this power asymmetry without violating the homogeneity constraint. The mechanism requires the introduction of a large-amplitude superhorizon perturbation to the curvaton field, possibly a pre-inflationary remnant or a superhorizon curvaton-web structure. The model makes several predictions, including non-Gaussianity and modifications to the inflationary consistency relation, that will be tested with forthcoming CMB experiments.

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