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Paper   IPM / Astronomy / 12601
School of Astronomy
  Title:   Effects of Variable Newton Constant During Inflation
1.  Ali Akbar Abolhasai
2.  Hassan Firouzjahi
3.  Mahdiyar Noorbala
  Status:   Published
  Journal: Phys. Rev. D
  Vol.:  86
  Year:  2012
  Supported by:  IPM
In this paper the effects of time-dependent Newton constant G during inflation are studied. We present the formalism of curvature perturbations in an inflationary system with time-dependent Newton constant. As an example we consider a toy model in which G undergoes a sudden change during inflation. By imposing the appropriate matching conditions the imprints of this sharp change in G on curvature perturbation power spectrum are studied. We show that depending on whether G increases (decreases) during the transition the amplitude of curvature perturbations on large scales decreases (increases). In our model with a sudden change in G a continuous sinusoidal modulations of curvature power spectrum is induced which can be detected on CMB. In a realistic scenarioin which the change in G has some finite time-scales, we expect this sinusoidal modulations to be damped on short scales.The generated feature may be used to explain the observed glitches on CMB power spectrum. This puts a bound on ∆G during inflation roughly the same order as current bounds on ∆G during entire observed age of the universe.

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