Constraint-preserving boundary conditions for the Einstein evolution system

Mark Scheel
California Institute of Technology

New boundary conditions are constructed and tested numerically for a general first-order form of the Einstein evolution system. These conditions prevent constraint violations from entering the computational domain through timelike boundaries and allow the simulation of isolated systems by preventing physical gravitational waves from entering the computational domain. These new boundary conditions are shown to be effective in limiting the growth of constraints in 3D non-linear numerical evolutions of dynamical single-black-hole spacetimes.