Marek Abramowicz (University of Gothenburg, Sweden) and Nishanth Gudapati (CSMA Fellow, Harvard)

Date: 

Tuesday, December 4, 2018, 1:30pm to 2:30pm

Location: 

BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)

Marek Abramowicz (University of Gothenburg, Sweden)

Title: How to search for a signal from alien civilizations?

Summary: I argue that sufficiently advanced alien civilizations would construct a very special type of transmitter, with unique properties that I describe, to signal their presence to the whole Galaxy.

Nishanth Gudapati (CSMA Fellow, Harvard)

Title: Gravitational Lensing for Stationary Spacetimes: A Finsler Geometry Approach

Abstract: A goal of the mathematical studies of gravitational lensing is to establish a relation between observables using geometric and topological information of the optical metric. In the work of Gibbons-Werner (2008), such a relation is established between the deflection angle of observation and the Gauss curvature of the optical metric of a static spacetime. Subsequently, this result was extended to a relation between the deflection angle and the geometric mass of the static spacetime. In view of the fact that the corresponding optical geometry of static spacetimes is Riemannian, the Gauss-Bonnet theorem was used in a fundamental way. In contrast with static spacetimes, the optical metric for stationary spacetimes is of Randers-Finsler type. In this talk we shall discuss some results on Finsler geometry approach for gravitational lensing in stationary spacetimes. Joint with Marcus Werner (Kyoto University).