7 papers
Energy of Isolated Systems at Retarded Times as the Null Limit of Quasilocal Energy
J. D. Brown, S. R. Lau, J. W. York
We define the energy of a perfectly isolated system at a given retarded time as the suitable null limit of the quasilocal energy . The result coincides with the Bondi-Sachs mass…
Well Posed Reduced Systems for the Einstein Equations
Y. Choquet-Bruhat, J. W. York
We review some well posed formulations of the evolution part of the Cauchy problem of General Relativity that we have recently obtained. We include also a new first order symmetric…
Geometrical Hyperbolic Systems for General Relativity and Gauge Theories
A. Abrahams, A. Anderson, Y. Choquet-Bruhat +1
The evolution equations of Einstein's theory and of Maxwell's theory---the latter used as a simple model to illustrate the former--- are written in gauge covariant first order symm…
3+1 General Relativity in Hyperbolic Form
A. M. Abrahams, J. W. York
This paper focuses on the imposition of boundary conditions for numerical relativity simulations of black holes. This issue is used to motivate the discussion of a new hyperbolic f…
Mixed Elliptic and Hyperbolic Systems for the Einstein Equations
Y. Choquet-Bruhat, J. W. York
We analyse the mathematical underpinnings of a mixed hyperbolic-elliptic form of the Einstein equations of motion in which the lapse function is determined by specified mean curvat…
Einstein and Yang-Mills theories in hyperbolic form without gauge-fixing
A. Abrahams, A. Anderson, Y. Choquet-Bruhat +1
The evolution of physical and gauge degrees of freedom in the Einstein and Yang-Mills theories are separated in a gauge-invariant manner. We show that the equations of motion of th…