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Imprints of a primordial preferred direction on the microwave background

Ackerman, Lotty and Carroll, Sean M. and Wise, Mark B. (2007) Imprints of a primordial preferred direction on the microwave background. Physical Review D, 75 (8). Art. No. 083502. ISSN 2470-0010.

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Rotational invariance is a well-established feature of low-energy physics. Violations of this symmetry must be extremely small today, but could have been larger in earlier epochs. In this paper we examine the consequences of a small breaking of rotational invariance during the inflationary era when the primordial density fluctuations were generated. Assuming that a fixed-norm vector picked out a preferred-direction during the inflationary era, we explore the imprint it would leave on the cosmic microwave background anisotropy, and provide explicit formulas for the expected amplitudes <almal[sup [prime]]m[sup [prime]]*> of the spherical-harmonic coefficients. We suggest that it is natural to expect that the imprint on the primordial power spectrum of a preferred spatial direction is approximately scale-invariant, and examine a simple model in which this is true.

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Carroll, Sean M.0000-0002-4226-5758
Additional Information:©2007 The American Physical Society (Received 29 January 2007; published 5 April 2007) Dragan Huterer near its completion. This research was supported in part by the U.S. Department of Energy and by the David and Lucile Packard Foundation.
Issue or Number:8
Record Number:CaltechAUTHORS:ACKprd07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8562
Deposited By: Archive Administrator
Deposited On:20 Aug 2007
Last Modified:02 Oct 2019 23:52

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