|Date: Thursday, September 26, 2019
Location: 4088 East Hall (4:00 PM to 5:00 PM)
Title: Evaluating Quasi-local Angular Momentum and Center-of-Mass at Null Infinity
Abstract: We calculate the limits of the quasi-local angular momentum and center-of-mass defined by Chen-Wang-Yau for a family of spacelike two-spheres approaching future null infinity in an asymptotically flat spacetime admitting a Bondi-Sachs expansion. Our result complements earlier work of Chen-Wang-Yau, where the authors calculate the quasi-local energy and linear momentum at null infinity. Working in the center-of-mass frame, i.e. assuming vanishing of linear momentum at null infinity, we obtain explicit expressions for the angular momentum and center-of-mass at future null infinity in terms of the observables appearing in the Bondi-Sachs expansion of the spacetime metric. This is joint work with Ye-Kai Wang and Shing-Tung Yau.
Speaker: Jordan Keller
Institution: Harvard, Black Hole Initiative, Cambridge MA