Dynamical tidal response of neutron stars from scattering amplitudes

Dates

2026-09-22 14:00
Dates
2026-09-22 15:30

Localisation / Location

APC

Salle / Local

483A

Orateur/Orator

Saketh Muddu

Affiliation

ICTS

Pays / Country

India

Type d'évènement / Type of event

Equipe(s) organisatrice(s) / Organizing team(s)

Tidal effects shape the late inspiral of binaries containing neutron stars and carry information about the neutron-star equation of state. Standard treatments either rely on a low-frequency expansion, which becomes inadequate near stellar resonances, or assume that the star’s internal dynamics can be modelled using harmonic oscillators. I will present an amplitude-based framework that avoids both assumptions and extracts the frequency-dependent tidal response within a worldline effective field theory. This is achieved by matching gravitational-wave scattering amplitudes calculated using relativistic stellar perturbation theory and the effective theory. The framework allows a systematic post-Newtonian (PN) expansion while retaining stellar resonances at every order. I will show that the resulting response recovers the known static limit and captures stellar resonances and their gravitational-wave damping, and present results needed through relative 3PN order. I will also discuss the subtraction of point-particle contributions and the renormalisation required at higher PN orders. I will conclude by outlining how this response can be incorporated into a binary Hamiltonian in the PN-EFT framework.

Mail à l'APC tous
Yes