Solving Einstein's Equations the Generalized Harmonic Way

Constraint Damping Generalized Harmonic System
Pretorius (based on a suggestion from Gundlach, et al.) modified
the GH system by adding terms proportional to the gauge
constraints:
[
0 = R ab − ∇ (a C b) + γ 0 n (a C b) − 1 2 ψ ab n c C c
],
where n a is a unit timelike vector field. Since C a = H a + Γ a
depends only on first derivatives of the metric, these additional
terms do not change the hyperbolic structure of the system.
Lee Lindblom (Caltech) GH Einstein CCRG-RIT – 10/17/2008 10 / 34