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Paper IPM / Astronomy / 12601  


Abstract:  
In this paper the effects of timedependent Newton constant G during inflation are studied.
We present the formalism of curvature perturbations in an inflationary system with timedependent 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 timescales, 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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