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Thursday, June 06, 2024
09:30 AM - 10:30 AM
CNLS Conference Room (TA-3, Bldg 1690)

Seminar

A POSTQUANTUM THEORY OF CLASSICAL GRAVITY

Jonathan Oppenheim
University College London, England

I will present a consistent theory of classical systems coupled to quantum ones via the path integral formulation. Inthe classical limit, this is the path integral for stochastic processes like Brownian motion. We then apply the formalismto general relativity, since it’s reasonable to question whether spacetime should have a quantum nature givenit’s status within quantum field theory. In contrast to perturbative quantum gravity, the pure gravity theory is renormalisable.The theory introduces a dimensionless coupling constant which controls the degree of diffusion in thegravitational field and runs to zero at short distances. Because of the stochastic nature of the theory, we find a deviationfrom general relativity at low acceleration which results in anomalous behavior of the gravitational field. Thisallows for both tabletop experiments and astrophyscical tests of the nature of spacetime in comparison to quantumgravity and cold dark matter.

Bio: Jonathan Oppenheim is a professor of physics at University College London. He is an expert in quantum informationtheory and quantum gravity. Oppenheim published a proposal in 2023 for a hybrid theory that couplesclassical general relativity with quantum field theory. According to this proposal, spacetime is not quantized butsmooth and continuous, and is subject to random fluctuations.