How much Einstein equation is enough Einstein equation?

Josh Mathews (National University of Singapore)

Time:

11AM Wednesday, 12 November 2025

Location:

UCD Confucius Institute, Room 1.01

Fundamental physics and astronomy with gravitational waves require accurate models to infer the properties of the source of detected signals. Upcoming gravitational wave detectors such as LISA will observe signals from binaries with asymmetric masses including extreme- and intermediate- mass-ratio inspirals (EMRIs/IMRIs). As the source populations of current detectors favour comparable mass-binaries and more simple dynamics, inference-ready models that target asymmetric binaries are few and the understanding of the systematics of such models is limited, relying in part on simple scaling arguments. EMRIs are particularly important for tests of General Relativity, and those tests can be muddied by poor understanding of their model systematics.

In this talk, I will outline how to design models that are representative of the future state-of-the-art (with controlled modelling errors) while the necessary computations are still in development. I will provide simple examples of how we can study accuracy requirements, model faithfulness, and implications on signal detection and measurement biases. I will conclude that, despite sounding boring, model systematics are quite interesting and critically important.