The Geneva Symmetry Group is happy to announce a talk by Viktoria Kabel (Vienna) this coming week. Her talk (abstract below) will be on
Wednesday, 10 May 2023, in Room L208 (Landolt), 16:15-17:45:
Viktoria Kabel (Vienna): Quantum Symmetries for Spacetimes in Superposition
When describing a physical system, it is very common to do so with respect to a reference frame – a ruler used to determine the position of a particle, for example, or a clock, which tracks the time that elapses while it is moving. Usually, reference frames are treated as purely classical objects with well-defined properties. But what happens if we take into account the quantum properties of the reference frame itself? In this talk, I will give an introduction to the basic idea and formalism of quantum reference frames, which aims to address this question. Moreover, I will explain how these generalised reference frames can be used to extend the classical symmetries of a theory to the quantum level. Of particular interest in this regard is the generalisation of the diffeomorphism invariance of classical general relativity to an invariance under quantum diffeomorphisms. This not only provides a new perspective from which to study scenarios involving superpositions of spacetimes but also raises and reinforces important conceptual questions regarding the meaning of spacetime points and the identification of objects across different branches of a superposition.
In terms of technical difficulty, this talk rates 4/5 Einsteins.