Identifying the nature of dark matter using the cosmic web

Cosmic observations emphatically demonstrate that most of the Universe's matter is invisible to light. "Dark matter" (DM) is the scaffold for the Universe, gravitationally attracting ordinary visible matter, and thus is essential to the formation of galaxies, stars, planets and life. Understanding the nature of DM is fundamental to understanding the origin of humanity, but the constituents of DM (particles and interactions) remain a mystery.

This is a critical moment when null results for the traditionally-favoured DM candidate (weakly interacting massive particles) are driving an explosion in well-motivated DM theories that urgently need new discovery strategies. We will imminently map the Universe's large-scale structure with unparalleled fidelity in surveys like Rubin. These surveys will provide a new, powerful testbed for microphysical DM models that current direct detection technology cannot probe, but which cause detectable cosmic signatures — if the theoretical modelling challenge is solved. As ERF at the pre-eminent astrostatistics group at Imperial College London, I will solve this challenge to detect or exclude the most compelling DM theories by the distinctive gravitational signatures they imprint in the cosmic web of structure. My vision is, thus, to transform how we search for the nature of dark matter by developing precision cosmological structure formation models for novel DM theories, where cosmological observations provide the most powerful — or often only — way to search for DM candidates.

I will definitively detect or exclude wave-like cosmic web effects from ultra-light axion DM (ULDM), whose discovery could point towards a "theory of everything" that seeks to explain all physical phenomena in a single set of laws. I will improve, by a factor of 25, constraints on nuclear/electronic interaction cross sections for light (sub-GeV) particle DM probing novel DM production mechanisms like freeze-in. I pioneered AI techniques to map accurately...