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Caltech

High Energy Theory Seminar

Wednesday, May 7, 2025
11:00am to 12:00pm
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Online and In-Person Event
Quantum mechanics and observers for gravity in a closed universe
Misha Usatyuk, KITP, UC Santa Barbara,

Recent arguments based on the gravitational path integral have given fairly compelling evidence that the Hilbert space of quantum gravity in a closed universe is one-dimensional. This presents a problem: how can this be consistent with the complexity of our own experiences? We propose an observer must be included, and give a framework and set of rules to include an observer in the closed universe. With the observer, the dimensionality of the closed universe Hilbert space becomes e^{S_Ob} where S_Ob is the number of degrees of freedom of the observer.

The talk is in 469 Lauritsen.

Contact [email protected] for Zoom information.