Celestial holography and celestial amplitudes

• Grant number: 25/26536-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: February 01, 2026
• End date: February 28, 2029
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Gabriel Santos Menezes
• Grantee: Agata Grechko
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 25/02861-0 - Scattering amplitudes in Gauge theories and gravity, AP.JP

Abstract

The celestial holography program is an attempt to apply the holographic principle to space-times with zero cosmological constant. On the one hand, this is motivated by the success of AdS/CFT. Indeed, the ability to similarly apply such duality to answer non-perturbative questions about quantum gravity as well as having a top-down string construction of celestial conformal field theories are ultimate goals. However, it can also be seen as an approach inspired by conformal field theory over amplitudes and previous S-matrix programs: if we have an intrinsic description of consistent celestial conformal field theories, we can hope to use CFT-bootstrap style machinery to compute and constrain the scattering.While several dictionary entries have been discovered and new insights into bulk theory have emerged through this proposal, developing an intrinsic definition of a CCFT and proposing the concrete construction of dual pairs of theories in the bulk and on the boundary remains a major challenge.Given this scenario, this research project proposes the following goals:* We currently lack an understanding of the basic aspects of holographic correspondence, such as the precise ways in which locality, unitarity and causality are encoded in CCFTs. On the other hand, it would be interesting to understand in more detail the relationship of celestial holography and celestial amplitudes with the KMOC formalism. Indeed, amplitudes with zero-energy gravitons provide a new perspective on the choice of the BMS frame for radiative observables.* On the other hand, although the so-called w¿ algebra can be extracted from the gravitational phase space of asymptotically flat space-times, the role of self-dual conditions is unclear, and thus it is also unclear which sector of the gravitational dynamics is captured by this symmetry. It would be interesting to know whether modern on-shell amplitude methods could be useful here.* We intend to investigate in depth the classical limit of the electromagnetic and gravitational Compton amplitude at the tree level involving massive particles of generic spin in the light of the celestial amplitudes formalism. Such amplitudes are relevant in the scattering of two Kerr black holes at order 2PM and also in the classical physics of wave scattering of massive particles at leading order.* A better understanding of massive celestial amplitudes would be especially interesting, as it could provide insights into the holographic description of non-perturbative asymptotically flat backgrounds, including black holes beyond their ultraboosted limits. We also wish to investigate this point in detail.We believe that this research project can contribute to the advancement of knowledge in the areas of celestial holography and asymptotic symmetries. The innovative and promising approach to scattering amplitudes can pave new paths to solve questions in theoretical physics and establish new connections. (AU)