Searching for New Physics with Pulsar Timing Arrays

Pulsar timing array (PTA) experiments aim to detect nHz-frequency gravitational waves using high-precision timing of millisecond pulsars. Multiple PTA collaborations have recently reported evidence for a stochastic gravitational wave background (SGWB), expected to arise predominantly from a population of inspiraling supermassive black hole binaries. In this talk, I will discuss how PTA experiments characterize the expected signal of the SGWB and present a new analysis technique that may better facilitate tests of general relativity. I will also discuss how timing data can be used to search for metric perturbations due to the presence of ultralight dark matter in the Galaxy.