# YTF 20

Dec 15 – 16, 2020
Centre for Particle Theory, Durham
Europe/London timezone

## Amplitudes and Backgrounds in Split Signature

Dec 16, 2020, 10:30 AM
30m
Teams (Centre for Particle Theory, Durham)

### Teams

#### Centre for Particle Theory, Durham

IPPP & Dept. Mathematical Sciences Durham University South Road Durham DH1 3LE

### Speaker

Mr Matteo Sergola (University of Edinburgh)

### Description

In this talk we are going to explore classical features of electromagnetic and gravitational radiation using quantum scattering amplitudes. To do so we analytically continue to a spacetime with $(2,2)$ signature $\eta_{\mu\nu}=\text{diag}(+,+,-,-)$. This allows us to consider, at leading order, 3-point on-shell amplitudes which would otherwise be identically zero in usual Minkowski spacetime. Our main result is that, in the classical limit, the scattered state is a coherent state which is the exponential of a 3-point amplitude. This occurs for both EM and GR radiation, which happen to be related to each other through the double copy. This opens up new possibilities to study gravitational wave physics with quantum field theory and unitarity methods.

Are you happy for your talk to be recorded? Yes No Yes 15-25 minutes

### Primary author

Mr Matteo Sergola (University of Edinburgh)

### Presentation materials

 MatteoSergola_YTF20.mp4 YTF_MatteoSergola.pdf