A film of the talk is available at: http://video.albanova.se/arc2021_18.html
One of the main unsolved problems in theoretical physics is combining quantum mechanics and general relativity. A central question is how to describe gravity as a quantum field, or if a quantum field description of gravity is even necessary. Baym and Ozawa in their paper "Two-slit diffraction with highly charged particles: Niels Bohr’s consistency argument that the electromagnetic field must be quantized" (PNAS, 106:3035–3040 (2009)) presented a thereto unpublished argument by Bohr, and considered towards the end this question for the gravitational field. Belenchia at al in their paper "Quantum superposition of massive objects and the quantization of gravity" (Physical Review D 98:1–9 (2018)) come to a different conclusion. In this talk these two Gedankenexperiments will be analyzed, compared, and combined. Assuming the Planck length as a fundamental lower bound on distance measurability, it is found that a quantum field theory of gravity is not a logical necessity from these types of considerations, in agreement with Baym and Ozawa.
This is joint work with with E Aurell and I Pikovski.
The seminar will be in blended form. For those connecting via zoom: https://stockholmuniversity.zoom.us/j/65464177460
For those participating in real life, the seminar room is FA31. KTH and SU recommendations apply. In particular, the maximum number of participants in the seminar room is eight (8).