Conformal gravity and transformations in the symmetric teleparallel framework

Abstract

Conformal symmetries appear in many parts of physics and play a unique role in exploring the Universe. We consider the possibility of constructing conformal theories of gravity in the symmetric teleparallel gravity framework, where gravitation is expressed through nonmetricity rather than curvature or torsion. We demonstrate that it is possible to formulate a family of conformal theories with second-order field equations and have the metric tensor as the fundamental variable. Moreover, we consider the addition of a scalar field to the theory, and compare the results to the teleparallel gravity setting. Finally, we present the scalar-tensor representation of modified symmetric teleparallel theories, and among others we show that there is an interesting subcase that has the possibility of playing the role of dark energy.