Is gravity actually the curvature of spacetime?
Abstract
The Einstein equations, apart from being the classical field equations of General Relativity, are also the classical field equations of two other theories of gravity. As the experimental tests of General Relativity are done using the Einstein equations, we do not really know if gravity is the curvature of a torsionless spacetime or torsion of a curvatureless spacetime or if it occurs due to the nonmetricity of a curvatureless and torsionless spacetime. However, as the classical actions of all these theories differ from each other by the boundary terms, and the Casimir effect is a boundary effect, we propose that a novel gravitational Casimir effect between superconductors can be used to test which of these theories actually describe gravity.
 Publication:

International Journal of Modern Physics D
 Pub Date:
 2019
 DOI:
 10.1142/S0218271819440218
 arXiv:
 arXiv:1905.04372
 Bibcode:
 2019IJMPD..2844021B
 Keywords:

 Teleparallel gravity;
 curvature of spacetime;
 Casimir effect;
 General Relativity and Quantum Cosmology
 EPrint:
 Essay received an honorable mention in the Gravity Research Foundation Essay Competition 2019. 7 pages