Quantum superpositions of spacetimes and black holes

by Magdalena Zych (Stockholm University)

Thursday 12 Oct 2023, 13:00 → 15:00 Europe/Stockholm

AlbaNova C4:3059 - Café Planck (AlbaNova Main Building)

If relativistic gravitation has a quantum description, it is meaningful to consider a spacetime metric sourced by a non classical state of matter such as a black hole in superposition of masses. But how might such a superposition be described of detected by observers in such spacetime. I will present a framework proposed for studying “superpositions of spacetimes” via indirect measurements---on test particles residing in such spacetime. I will then show how it can be applied to a black hole in a superposition of masses where the dynamics of the test particle exhibits signatures of effects reminiscent of Bekenstein’s conjecture concerning the quantized mass spectrum of black holes in quantum gravity. I will close with remarks on the importance of identifying scenarios that are genuinely quantum-gravitational, notably with reference to recent proposals to test gravitationally induced entanglement.