“School of Astronomy”

Back to Papers Home
Back to Papers of School of Astronomy

Paper   IPM / Astronomy / 12601
School of Astronomy
  Title:   Effects of Variable Newton Constant During Inflation
  Author(s): 
1.  A. A. Abolhasai
2.  H. Firouzjahi
3.  M. Noorbala
  Status:   Published
  Journal: Phys. Rev. D
  Vol.:  86
  Year:  2012
  Supported by:  IPM
  Abstract:
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 $\Delta G$ during inflation roughly the same order as current bounds on $\Delta G$ during entire observed age of the universe.

Download TeX format
back to top
scroll left or right