Observational constraints on patch inflation in noncommutative spacetime

Gianluca Calcagni, Shinji Tsujikawa

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53 Citations (Scopus)


We study constraints on a number of patch inflationary models in noncommutative spacetime using a compilation of recent high-precision observational data. In particular, the four-dimensional general relativistic (GR) case, the Randall-Sundrum (RS), and the Gauss-Bonnet brane world scenarios are investigated by extending previous commutative analyses to the infrared limit of a maximally symmetric realization of the stringy uncertainty principle. The effect of spacetime noncommutativity modifies the standard consistency relation between the tensor spectral index and the tensor-to-scalar ratio. We perform likelihood analyses in terms of inflationary observables using new consistency relations and confront them with large-field inflationary models with potential [Formula Presented] in two classes of noncommutative scenarios. We find a number of interesting results: (i) the quartic potential ([Formula Presented]) is rescued from marginal rejection in the class 2 GR case, and (ii) steep inflation driven by an exponential potential ([Formula Presented]) is allowed in the class 1 RS case. Spacetime noncommutativity can lead to blue-tilted scalar and tensor spectra even for monomial potentials, thus opening up a possibility to explain the loss of power observed in cosmic microwave background anisotropies. We also explore patch inflation with a Dirac-Born-Infeld tachyon field and explicitly show that the associated likelihood analysis is equivalent to the one in the ordinary scalar field case by using horizon-flow parameters. It turns out that tachyon inflation is compatible with observations in all patch cosmologies even for large [Formula Presented].

Original languageEnglish
Number of pages1
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number10
Publication statusPublished - 2004
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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