Non-commutative inflation and the CMB

Shinji Tsujikawa*, Roy Maartens, Robert Brandenberger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

131 Citations (Scopus)


Non-commutative inflation is a modification of standard general relativity inflation which takes into account some effects of the space-time uncertainty principle motivated by ideas from string theory. The corrections to the primordial power spectrum which arise in a model of power-law inflation lead to a suppression of power on large scales, and produce a spectral index that is blue on large scales and red on small scales. This suppression and running of the spectral index are not imposed ad hoc, but arise from an early-Universe stringy phenomenology. We show that it can account for a loss of power on the largest scales that may be indicated by recent WMAP data. Cosmic microwave background anisotropies carry a signature of these very early Universe corrections, and can be used to place constraints on the parameters appearing in the non-commutative model. Applying a likelihood analysis to the WMAP data, we find the best-fit value for the critical wavenumber k* (which involves the string scale) and for the exponent p (which determines the power-law inflationary expansion). The best-fit value corresponds to a string length of Ls ∼ 10-28 cm.

Original languageEnglish
Pages (from-to)141-148
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3-4
Publication statusPublished - 2003 Nov 13
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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