We present a new choice of initial data for binary black hole simulations that significantly improves the efficiency of high-spin simulations. We use spherical Kerr-Schild coordinates, where the horizon of a rotating black hole is spherical, for each black hole. The superposed spherical Kerr-Schild initial data reduce the runtime by a factor of 2 compared to standard superposed Kerr-Schild for an intermediate resolution spin-0.99 binary-black-hole simulation. We also explore the possibility of delaying the transition from the initial data gauge to the evolution gauge, which produces an additional speed-up of 1.3.
@article{arxiv.2108.02331,
title = {Efficient simulations of high-spin black holes with a new gauge},
author = {Yitian Chen and Nils Deppe and Lawrence E. Kidder and Saul A. Teukolsky},
journal= {arXiv preprint arXiv:2108.02331},
year = {2021}
}