Heidelberg 2022 – scientific programme
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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik
MP 5: Quantum information
MP 5.1: Invited Talk
Wednesday, March 23, 2022, 11:00–11:30, MP-H5
Falling through masses in superposition: quantum reference frames for indefinite metrics — Anne-Catherine de la Hamette1,2, Viktoria Kabel1,2, Esteban Castro-Ruiz3, and •Caslav Brukner1,2 — 1Institute for Quantum Optics and Quantum Information, Vienna, Austria — 2Faculty of Physics, University of Vienna, Vienna, Austria — 3Institute for Theoretical Physics, ETH Zürich, Zürich, Switzerland
The current theories of quantum physics and general relativity on their own do not allow us to study situations in which the gravitational source is quantum. In my talk, I will propose a strategy to determine the dynamics of objects in the presence of mass configurations in superposition, and hence an indefinite spacetime metric, using quantum reference frame (QRF) transformations. Specifically, I will show that as long as the mass configurations in the different branches are related via isometries, one can use an extension of the current framework of QRFs to "quantum isometries" to change to a frame in which the mass configuration becomes definite. Assuming covariance of dynamical laws under quantum coordinate transformations, this allows to use known physics to determine the dynamics. I will apply this procedure to find the motion of a probe particle and the behavior of clocks near the mass configuration, and thus find the time dilation caused by a gravitating object in superposition.