Triangle Seminars
Monday, 15 Sep 2025
AI & the Future of Maths
📍 London
Yang-Hui He
(LIMS)
Abstract:
https://www.rigb.org/whats-on/mathematics-rise-machines
Royal Institution Public Lecture on AI & the future of Maths.
https://www.rigb.org/whats-on/mathematics-rise-machines
Royal Institution Public Lecture on AI & the future of Maths.
Posted by: Yang-Hui He
Thursday, 18 Sep 2025
Extracting spinning two-body observables from S-matrix
📍 London
Canxin Shi
(Institute of Theoretical Physics, CAS (Beijing))
Abstract:
High-precision prediction of the two-body problem is at the center of gravitational-wave physics. 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.
High-precision prediction of the two-body problem is at the center of gravitational-wave physics. 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.
Posted by: Morteza S. Hosseini