The null geodesics of charged and non-charged black hole in mimetic gravity

Abstract

The null geodesics around the charged black hole spacetimes are investigated in the mimetic gravity framework when Einstein's gravity is coupled to a nonlinear electromagnetic field. The photon paths in nonlinear electrodynamics are geodesics of the effective metric which is determined by the background metric and the particular nonlinear theory considered. The nonlinear effects are represented by a quadruple moment and appear as a correction term to Reissner Nordstrom (RN) metric and Reissner Nordstrom-anti-de Sitter (RN-(A)dS) in cylindrical metric. Remarkably, the nonlinear effects prevent the circular orbits around black holes, and the presence of the mimetic field can change the repulsive character of dS space to the attractive one. Also, the effect of the mimetic parameter manifests itself in the stronger or weaker gravity of the black hole.