 Nordström's theory of gravitation

Nordstrom's scalar theory restricts the spacetime metric to the conformally flat form $g_{\mu \nu }={\phi }^2{\eta }_{\mu \nu }$. Its null geodesics have the same unparametrized paths as those of the Minkowski metric, so the theory predicts no gravitational bending of light.

As of my last knowledge update in October 2023, there is no widely recognized or established theory of gravitation known specifically as "Nordström's theory.