Imprints of a Primordial Preferred Direction on the Microwave Background

Jan, 2007
7 pages
Published in:
  • Phys.Rev.D 75 (2007) 083502,
  • Phys.Rev.D 80 (2009) 069901 (erratum)
e-Print:
Report number:
  • CALT-68-2626

Citations per year

200720122017202220250102030
Abstract: (arXiv)
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 <almalm><a_{lm}a_{l'm'}^*> 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.
Note:
  • 7 pages, no figures; v5: Corrections, as well as use of more standard convention, in section II
  • 98.80.Cq
  • 99.10.Cd
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