1–5 Sept 2026
University of Sussex
Europe/London timezone

Unitarity at all scales: Towards 2-to-2 scattering of scalars in Asymptotically Safe Quantum Gravity.

3 Sept 2026, 11:20
20m
Terrace Room (Bramber House)

Terrace Room

Bramber House

Speaker

Angelo Portas Chiesa (University of Sussex)

Description

Asymptotically safe quantum gravity provides a UV completion of metric quantum gravity, with and without matter. This is achieved via scale invariance in the strongly coupled regime, entailing finiteness at all scales. Compared to the existence of the scaling symmetry, the study of the unitarity of the theory is still in its infancy. In this talk, I present the asymptotically safe scattering amplitude of two-to-two scalar fields.
Focusing on the mediated amplitude, we use modern functional renormalisation group methods to obtain non-perturbative momentum-dependent results for the resummed scalar-graviton vertex and propagators.
Together with reconstruction and analytic continuation techniques. These are corredated by the gravitational contribution to the contact amplitude, whose we resum directly in Lorentzian signature.
This allows us to study the non-perturbative amplitude and cross-section.
The cross-section is an observable of the theory; it is compatible with GR at small energies, and it respects unitarity in the UV.

Affiliation University of Sussex
Link to paper https://arxiv.org/abs/2603.10168
Career status PhD student

Author

Angelo Portas Chiesa (University of Sussex)

Co-authors

Presentation materials

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