Source coupled to the massive scalar field orbiting a stellar object

Abstract

In this work we analyze, using quantum field theory at tree level, the massive scalar radiation emitted by a source in uniform circular motion in Minkowski spacetime, assuming Newtonian gravitation, and in the curved spacetime of a chargeless static black hole, assuming general relativity. the computations are performed analytically for the case of Minkowski spacetime and numerically for the case of Schwarzschild spacetime. We verify, for stable circular orbits, that the emission rate and the emitted power in Schwarzschild spacetime are smaller than the ones obtained in Minkowski spacetime assuming Newtonian gravitation. We obtain that only a small amount of the emitted radiation is absorbed by the black hole. We also verify that the difference between Schwarzschild and Minkowski cases decreases when the mass of field is increased. The amount of radiation absorbed by the black hole increases for higher values of the mass of the scalar field.