1202.4639 (Thomas W. Baumgarte)

An alternative approach to solving the Hamiltonian constraint    [PDF]

Thomas W. Baumgarte

Solving Einstein's constraint equations for the construction of black hole
initial data requires handling the black hole singularity. Typically, this is
done either with the excision method, in which the black hole interior is
excised from the numerical grid, or with the puncture method, in which the
singular part of the conformal factor is expressed in terms of an analytical
background solution, and the Hamiltonian constraint is then solved for a
correction to the background solution that, usually, is assumed to be regular
everywhere. We discuss an alternative approach in which the Hamiltonian
constraint is solved for an inverse power of the conformal factor. This new
function remains finite everywhere, so that this approach requires neither
excision nor a split into background and correction. In particular, this method
can be used without modification even when the correction to the conformal
factor is singular itself. We demonstrate this feature for rotating black holes
in the trumpet topology.

View original: http://arxiv.org/abs/1202.4639