GRChombo : Numerical Relativity with Adaptive Mesh Refinement

TL;DR

GRChombo is a new numerical relativity code that utilizes adaptive mesh refinement to efficiently and accurately simulate complex spacetime phenomena like black hole mergers, enabling previously infeasible physics studies.

Contribution

The paper introduces GRChombo, a novel AMR-based numerical relativity code supporting complex mesh hierarchies and parallelism, improving simulation capabilities and setup simplicity.

Findings

Successfully evolved binary black hole mergers

Demonstrated stable scalar collapse simulations

Showcased performance and accuracy of the code

Abstract

In this work, we introduce GRChombo: a new numerical relativity code which incorporates full adaptive mesh refinement (AMR) using block structured Berger-Rigoutsos grid generation. The code supports non-trivial "many-boxes-in-many-boxes" mesh hierarchies and massive parallelism through the Message Passing Interface (MPI). GRChombo evolves the Einstein equation using the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. The AMR capability permits the study of a range of new physics which has previously been computationally infeasible in a full 3+1 setting, whilst also significantly simplifying the process of setting up the mesh for these problems. We show that GRChombo can stably and accurately evolve standard spacetimes such as binary black hole mergers and scalar collapses into black holes, demonstrate the performance characteristics of our code, and discuss various physics problems which stand to benefit from the AMR technique.