A Thought Experiment to Determine the Quantum Nature of Space-time

Synopsis

The most important unsolved problem in Physics is the unification of General Relativity (GR) and Quantum Mechanics (QM). Almost everyone agrees that to achieve this unification, the gravitational field needs to be quantized. However, there is no agreement on whether space-time fundamentally possesses quantum features.

Moreover, when it comes to unifying GR and QM, there is an ongoing discussion about the scope of validity of each of these theories and how to resolve the contradictions that have arisen.

In this talk, I will discuss a related thought experiment recently proposed by D. Garcia et al [1]. It has been designed so that the theory behind it is based only on a few features of GR and QM. The experiment's creators claim that their theory's assumptions are independent of the contradictions between the two theories. I will show how their thought experiment demonstrates that if these assumptions hold, it violates Bell's inequality, suggesting that space-time may not be classical.

[1] D. Pitalúa-García, Is space-time quantum?, arXiv ID, e.g., 2109.02608.