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10:00 (CET) March 15,  Prof. Dr. Simon Haine (The Australian National University)

Title: Searching for Signatures of Quantum Gravity with Ultracold Quantum Gases


While a full theoretical quantum treatment of quantum gravity remains elusive, effective quantum field theories of gravity have been developed, by treating the quantum field as a perturbation from the classical solution. Low-energy laboratory-scale experiments are well within this perturbative regime. However, whether or not the gravitational field displays quantum properties, that is, if a quantum treatment is required at all, is a question that demands experimental resolution, with several proposed theories stating that the gravitational field may be fundamentally classical. Recently, there has been considerable interest in the possibility of low-energy experiments capable of distinguishing if the difference between a theory of gravity where the gravitational field is allowed to exist in a coherent quantum superposition, and theories where the gravitational field must remain classically valued. 

I explore the possibility of testing the quantum nature of the gravitational field with an ensemble of ultra-cold atoms. The use of many microscopic particles may circumvent some of the experimental obstacles encountered in recent proposals involving a pair of particles with mesoscopic mass. I employ multi-parameter estimation techniques, including the quantum and classical Fisher information to provide a criteria for the observability of the quantum effects, and compare to other recently proposed schemes. Crucially, I find that by preparing the appropriate initial state, interactions mediated via a quantum-valued gravitational field provide a signature that is distinct from classical gravitational interactions.


Thank you for your interest in our research. Get in touch with us for any questions or comments regarding research in the interface of quantum mechanics, field theory and gravity.

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