Graviton scattering in self-dual radiative space-times

Tim Adamo*, Lionel Mason, Atul Sharma

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The construction of amplitudes on curved space-times is a major challenge, particularly when the background has non-constant curvature. We give formulae for all tree-level graviton scattering amplitudes in curved self-dual (SD) radiative space-times; these are chiral, source-free, asymptotically flat spaces determined by free characteristic data at null infinity. Such space-times admit an elegant description in terms of twistor theory, which provides the powerful tools required to exploit their underlying integrability. The tree-level S-matrix is written in terms of an integral over the moduli space of holomorphic maps from the Riemann sphere to twistor space, with the degree of the map corresponding to the helicity configuration of the external gravitons. For the MHV sector, we derive the amplitude directly from the Einstein-Hilbert action of general relativity, while other helicity configurations arise from a natural family of generating functionals and pass several consistency checks. The amplitudes in SD radiative space-times exhibit many novel features that are absent in Minkowski space, including tail effects. There remain residual integrals due to the functional degrees of freedom in the background space-time, but our formulae have many fewer such integrals than would be expected from space-time perturbation theory. In highly symmetric special cases, such as SD plane waves, the number of residual integrals can be further reduced, resulting in much simpler expressions for the scattering amplitudes.

Original languageEnglish
Article number095002
JournalClassical and quantum gravity
Issue number9
Publication statusPublished - 4 May 2023

Keywords / Materials (for Non-textual outputs)

  • graviton scattering
  • QFT in curved spacetime
  • scattering amplitudes
  • self-duality
  • twistor theory


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