High Energy Theory Seminar

Friday, May 26, 2023
1:00pm to 2:00pm
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Online and In-Person Event
A New Supertranslation-Invariant Angular Momentum Flux in Gravitational Scattering
Massimo Porrati, New York University,

The angular momentum radiated in gravitational scattering can be changed by performing a supertranslation of the asymptotic metric, i.e. by adding radiation with infinite wavelenght to the metric. This puzzling property can be avoided by adopting a supertranslation-invariant definition of the angular momentum flux in general relativity. None of the definitions for the angular momentum flux in terms of asymptotic data currently available in the literature can reproduce the value necessary to obtain the correct radiation reaction effects in gravitational scattering. They also disagree with computations of the flux performed using scattering amplitudes and soft graviton theorems. In this talk I will present a new supertranslation-invariant definition of the angular momentum flux radiated during gravitational scattering. This definition uses only asymptotic metric data and reproduces the flux necessary to obtain the known radiation reaction effects in the center of mass frame.

I will also discuss some open problems and puzzles with the definition of the flux proposed in this talk.

In person attendees (469 Lauritsen) must have a valid Caltech ID.

Contact theoryinfo@caltech.edu for Zoom information.