EAS Publications Series
Volume 30, 2008Spanish Relativity Meeting - Encuentros Relativistas Españoles , ERE2007: Relativistic Astrophysics and Cosmology
|Page(s)||69 - 79|
|Published online||30 September 2008|
A. Oscoz, E. Mediavilla and M. Serra-Ricart (eds)
EAS Publications Series, 30 (2008) 69-79
Gauge and constraint degrees of freedom: from analytical to numerical approximations in General Relativity
Departament de Fisica, Universitat de les Illes Balears, Institute for Applied Computation with Community Code (IAC3)
The harmonic formulation of Einstein's field equations is considered, where the gauge conditions are introduced as dynamical constraints. The difference between the fully constrained approach (used in analytical approximations) and the free evolution one (used in most numerical approximations) is pointed out. As a generalization, quasi-stationary gauge conditions are also discussed, including numerical experiments with the gauge-waves testbed. The complementary 3+1 approach is also considered, where constraints are related instead with energy and momentum first integrals and the gauge must be provided separately. The relationship between the two formalisms is discussed in a more general framework (Z4 formalism). Different strategies in black hole simulations follow when introducing singularity avoidance as a requirement. More flexible quasi-stationary gauge conditions are proposed in this context, which can be seen as generalizations of the current “freezing shift” prescriptions.
© EAS, EDP Sciences, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.