Kevin Croker is an Assistant Research Scientist at Arizona State University in the School of Earth and Space Exploration working on the phenomenology of strong gravitation. He jointly holds an Affiliate Graduate Faculty position at the University of Hawai‘i at Manoa where he previously held a Postdoctoral Fellowship and earned his PhD in Physics. He is a Fulbright and NSF East-Asia and Pacific Summer Institutes alumnus and holds a BSc in Computer Science from Washington University in St. Louis
Title: Cosmological Coupling in the Era of the Dark Energy Spectroscopic Instrument
Abstract: Recent advances in General Relativity point toward unanticipated, and dynamic, relations between ultracompact objects and the universe they inhabit. The possibility for strongly gravitating systems, like astrophysical black holes (BHs) and their embedding cosmology, to directly interact has been dubbed "cosmological coupling." We focus on recent results from the DOE Stage IV Dark Energy (DE) Spectroscopic Instrument (DESI), which strongly suggest that DE is dynamical. Using typical empirical models for the cosmic star-formation rate density as a proxy to BH production, we show that the DESI-inferred time-evolution of DE is consistent with cosmologically coupled stellar-collapse BHs as the source of DE. The predicted cosmological expansion rate today, H_0 = 69.94 +/- 0.81 km/Mpc/s, is in excellent agreement with H_0 = 69.58 +/- 1.58 km/Mpc/s recently reported by the Chicago-Carnegie Hubble Program using Cepheid, Tip of the Red Giant Branch, and J-Region Asymptotic Giant Branch stellar distance-ladder calibrations. With DESI Redshift Space Distortions and Year 3 datasets on the horizon, we highlight exciting prospects for further observational confrontation in the near term.
arxiv: (JCAP, in press) https://arxiv.org/abs/2405.12282