Series:
The London Relativity and Cosmology Seminar
Speaker:
Fay Dowker (Imperial)
Date:
January 28th, 2015 at 16:30
Room:
See Talk Details
Abstract:
In the late 1980’s Rafael Sorkin predicted that the Cosmological Term
Lambda(today) should be observed to be, not zero, but of the order of magnitude of (H_0)^2,
which prediction turned out to be in agreement with current observational data. Sorkin used
a heuristic argument from Causal Set Theory — a discrete approach to quantum gravity — to make this
prediction. A more concrete model predicts that Lambda is not constant but fluctuates — even to
negative values — throughout cosmic history so that continuing evidence for constant Lambda
back to larger redshifts would be evidence against this model. I will explain the basics of causal set
quantum gravity and Sorkin’s argument. I will suggest that the current growing tension between high and low
redshift observations may be indicating that Lambda does indeed fluctuate. - Room 516