Double null evolution of a scalar field in Kerr spacetime

Abstract

We have developed and implemented a numerical scheme and code that computes the evolution of the massless scalar field wave equation in Kerr spacetime, using double null coordinates. The results show a smooth behavior across the event horizon, making it possible to give initial data outside the event horizon, evolve the scalar field across the horizon, and keep the evolution even inside the black hole. This is the first time that a double null evolution is performed for a scalar field in Kerr spacetime.