Speaker
Description
Gravitational-wave (GW) observations allow us to reconstruct the orbital dynamics of compact binaries with remarkable precision. When these systems evolve in dense environments—such as active galactic nucleus discs, nuclear star clusters, or dark matter structures—their surroundings can leave characteristic imprints on the GW phase evolution. These imprints open a new avenue for probing not only the distribution of dark matter, but also its microscopic properties.
In this talk, I will discuss how gravitational waves can be used to probe dark matter microphysics, including the mass and spin of its fundamental constituents.
I will present results from the first dedicated search for signatures of light scalar fields in the orbital dynamics of black hole binaries using LIGO–Virgo–KAGRA data. In particular, I will discuss the intriguing case of GW190728, whose signal shows features consistent with those expected from the presence of a light scalar field with a mass of order 10^{-12} eV, and assess the significance and interpretation of this result.
Finally, I will show how extreme-mass-ratio inspirals observed by LISA could measure the mass of ultralight dark matter particles, providing a purely gravitational probe of dark matter microphysics.