Robert Scherrer

Vanderbilt University, September 13, 12:00 pm

Cosmological Effects of a Rapidly Varying Gravitational Constant

Scalar-tensor theories of gravity lead naturally to a time-varying G. The consequences of a rapidly-varying G were first explored by Accetta and Steinhardt in 1991 and then generally ignored. I will discuss the motivation for such models and review the observational limits that can be placed on time-varying G. I will then discuss recent work with Anish Giri (Vanderbilt undergraduate) using big-bang nucleosynthesis to constrain these models. In the second part of talk, I will discuss possible future directions, including models with rapidly-oscillating G that can mimic a cosmological constant. I am hoping that this part of the talk can be an open discussion – there ought to be lots of interesting consequences from a rapidly oscillating value of G that have not been previously examined.