At its heart, general relativity is a geometric theory of gravitation in which spacetime is modelled as a four-dimensional Lorentzian manifold equipped with a metric tensor whose curvature encodes the ...

Diagrammatic representation of the entropic quantum gravity action. The action for gravity is given by the quantum relative entropy between the metric of the manifold and the metric induced by the ...

It stands among the most famous theories ever created, but the general theory of relativity did not spring into being with a single, astonishing paper like the special theory of relativity in 1905.

All bodies in a given gravitational field are thought to fall with the same acceleration. This idea, known as the equivalence principle, is central to our understanding of gravitational physics. It ...