Prof. Yi-Zen Chu
University of Minnesota, Duluth
Date 2017.02.24(Fri)
Time 14:00
Place S4-625
Abstract:
Despite being associated with particles of zero rest mass, electromagnetic and gravitational waves do not travel solely on the null cone in generic curved spacetimes. (That is, light does not always propagate on the light cone.) This inside-the-null-cone propagation of waves is known as the tail effect, and finding novel ways of understanding it in the strong field regime near a black hole may find applications for modeling the gravitational signals sought after by next-generation space-based detectors such as LISA.
Motivated by these considerations — and as a first step — I have been exploring techniques to understand the causal structure of scalar, electromagnetic and gravitational waves in cosmological spacetimes. I will describe my efforts to date, which include how the gravitational wave memory effects in 4D asymptotically flat spacetime generalize to the cosmological case.