Simulations of a scalar field on a black hole background

by the LSU group. This is using a code in which the discretization of the derivatives is done in such a way that one can prove a priori that the code will be stable.

In the first movie we see the propagation of a pulse of scalar field off-center of the black hole.

In the second movie we see the propagation of a pulse of scalar field with l=2 structure, as will correspond to the final ringdown of a black hole collision.

As can be seen both simulations run smoothly for about 100M, with virtually no reflections either at the excision or the exterior boundaries.