Welcome Room: Room 1077

A view of binary dynamics from infinity

• Radu Roiban

Room: Room 1077 Quantum field theory and scattering are attractive and powerful probes of gravitational interactions. In this talk we survey the current status of scattering-based calculations for the gravitational two-body problem, their application to the bound regime and their synergy with the (gravitational) self-force.

High Precision Gravitational Scattering: PM, MPM, SF, EFT, EOB, TF, NR and All That

• Thibault Damour

Room: Room 1077 The synergies between various approaches to the 2-body problem will be reviewed, as well as the role of the EOB formalism in concretizing these synergies. High-post-Newtonian-order connections between Tutti Frutti and Worldline EFT will be discussed.

From Black Hole Scattering to Gravitational Waveforms

• Gustav Mogull

Room: Room 1077 In this talk I will outline a full workflow from classical black hole scattering to producing gravitational waveforms in bound binary systems. This will include our recent computation of 5PM-1SF scattering observables using the Worldline Quantum Field Theory (WQFT) formalism, Effective-One-Body (EOB) resummation and comparisons with NR data both for scattering and bound orbits.

Discussion

• Maarten van de Meent

Room: Room 1077

Quantum spectral method

• Ofri Telem (The Hebrew University of Jerusalem)

Room: Room 1077

Numerical approaches to self-force calculations along scatter orbits

• Chris Whittall

Room: Room 1077 In this talk we will review the methods used to perform numerical calculations of the self-force along scatter geodesics in black hole spacetimes. Starting with a general introduction to the calculation of the self-force by mode-sum regularisation, we will move on to discuss two extant numerical platforms for calculating the scalar-field self-force along scatter geodesics, one of which solves the field equation in the time-domain [Phys. Rev. D 106, 104031] and the other in the frequency-domain [Phys. Rev. D 108, 064017]. We will only highlight the basic merits and limitations of each approach here; for details of the numerical results obtained using these codes, see the following talk by O. Long. We then summarise some new approaches currently under development, including a detailed look at a novel method that uses the Gegenbauer reconstruction technique to resolve some shortcomings of the existing frequency-domain approach. We conclude by discussing the outlook for extending numerical scalar field calculations to the full gravitational self-force problem.

Applications of numerical self-force scattering simulations

• Oliver Long

Room: Room 1077 Following the discussion of how to calculate the self-force on scattering orbits, I will discuss the applications of the results of these simulations. This starts with results from scalar self-force scattering, including radiated and absorbed fluxes, a resummation of post-Minkowskian that improves the faithfulness to the numerical results across the whole parameter space, and the use of scalar self-force information to perform self-consistent evolution in Numerical Relativity. I will continue by discussing the steps required to perform the first calculations of the gravitational self-force on a scattering orbit and present new results of the gravitational self-force radiated and absorbed fluxes.

Updates on Black Hole Scattering from Self Force

• Davide Usseglio

Room: Room 1077 In this talk I will discuss the general strategy employed for solving analytically the Teukolsky equation where the perturbation is sourced by a particle in a hyperbolic orbit. This method relies on a combination of post-Newtonian (PN) and post-Minkowskian (PM) expansion in order to extract analytical information and it has been used for studying the scattering of a scalar charge around a Schwarzschild black hole. In the second part of my talk I’ll discuss the state of our works in the gravitational case, highlighting the difficulties faced in going to high order in PM and PN for the computation of the waveform and the fluxes.

Extracting spinning two-body observables from S-matrix

• Canxin Shi

Room: Room 1077 I will present a novel method for extracting observables for two-body scattering systems from a set of generating functions, with full spin dependence. The approach uses the classical limit of the logarithm of the quantum S-matrix as generating functions. The 4-point matrix element of Log(S) gives the radial action, corresponding to conservative effects, whereas the higher-point contributions encode radiative information. The observables, such as momentum impulse, orbital angular momentum, and waveform, are obtained by applying differential operators, which are constructed from Dirac brackets and the generating functions, to the initial value of the observable. We demonstrate its power by calculating new high-precision results, including the impulse and spin kick for a probe in Kerr up to $O(G^6 s^4)$, and the change in angular momentum for generic masses up to $O(G^2 s^11)$. Via analytic continuation, we can also provide information about bound orbits, such as their fundamental frequencies.

Discussion

• Leor Barack

Room: Room 1077

Methods for computing observables in classical gravity

• Pierre Vanhove

Room: Room 1077 In this talk we will present various methods that have been developed recently for computing observables in classical gravity.

Self-force and Loops in Black Hole Scattering

• Gustav Jakobsen

Room: Room 1077 I present recent progress on the classical loop (post-Minkowskian) expansion of black-hole scattering and its relation to the self-force expansion. I will focus on how these expansions are organized within worldline quantum field theory and its diagrammatic framework. This includes our novel four-loop results, higher-spin observables, and open puzzles that point to future work.

Solving the Einstein equations by quantum field theory methods

• Poul Damgaard

Room: Room 1077 Inspired by the perturbiner method of quantum field theory I describe how to rephrase the perturbative solution of the Einstein equations in terms of an iterative scheme. As an application, I outline how to compute the metric outside a localized region of stationary matter to arbitrarily high order in the coupling G.

Discussion

• Mao Zeng

Room: Room 1077

Perturbative Computations from Curved Spacetimes

• Nabha Shah

Room: Room 1077 Given the impressive results for classical observables obtained by field theoretic approaches to gravitational systems, we can ask if these tools can help us in new regimes and problems of interest. Amplitude tools are particularly well suited to derive observables for the binary system in a post-Minkowskian expansion, where they have achieved complete results to fourth order in Newton's constant. However, obtaining strong field results is a complicated problem. From the perspective of perturbative quantum field theory, classical solutions in general relativity are remarkable objects; they make manifest a resummation of an infinite series of Feynman diagrams encoding information to all orders in Newton’s constant. I will describe an effective field theory formalism tailored for computations about nontrivial classical backgrounds, and present the potential, and hurdles, in combining advantages from classical gravitational and field theoretic techniques to address questions related to the binary inspiral problem.

Love Numbers and Self Force from Effective Field Theory

• Dimitrios Kosmopoulos

Room: Room 1077 I will introduce a new formalism that combines techniques from Effective Field Theory (EFT) with solutions to Black Hole Perturbation Theory. I will present new results obtained with this formalism for dynamical EFT Love numbers and discuss prospects for the computation of Self-Force observables.

Discussion

• Julio Parra-Martinez

Room: Room 1077