Search Talks

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.

Dark matter and neutrinos are elusive neutral matter filling up our Universe. The PandaX (Particle and Astrophysical Xenon) experiment, located in the China Jinping Underground Laboratory, is dedicated to searching for dark matter particles and studying the fundamental properties of neutrinos. The current running experiment, PandaX-4T, contains a sensitive time-projection-chamber with a 3.7-ton liquid xenon target. In this talk, after an overview, I will present recent results from PandaX-4T in dark matter direct detection, double beta decay of 136Xe, as well as solar neutrinos. I will also present a concrete plan for the next-generation xenon observatory in CJPL, PandaX-xT.