Abstract: I discuss the possibility that the ''dark energy'' that drives the accelerated expansion of the universe arises not from a conventional cosmological constant term in the gravitational action, but rather from a frame-dependent but Weyl scaling invariant action term. This action mimics the standard cosmological action in an unperturbed Friedmann-Robertson-Walker (FRW) cosmology, but has novel consequences both for black hole horizons and, the focus of this talk, for perturbations around the FRW solution. I discuss motivations for a Weyl invariant cosmological action, new insights it would give on old problems, and Implications for the recently much discussed ''Hubble Tension''. The talk keeps technicalities to a minimum, requiring only a basic knowledge of FRW cosmology and ordinary differential equations, and concludes with a list of problems for further study, some of which could be undergraduate paper or thesis topics.

# Gravity Initiative Lunch, Stephen Adler | IAS "Implications of a Frame-Dependent Dark Energy for the Spacetime Metric and "Hubble Tension""

Mon, Feb 24, 2020, 12:30 pm

Location:

Princeton Gravity Initiative, 4th Floor