298 research outputs found
Horizons in the near-equilibrium regime
Quasi-static systems are an important concept in thermodynamics: they are
dynamic but close enough to equilibrium that many properties of equilibrium
systems still hold. Slowly evolving horizons are the corresponding concept for
quasilocally defined black holes: they are "nearly isolated" future outer
trapping horizons. This article reviews the definition and properties of these
objects including both their mechanics and the role that they play in the
fluid-gravity correspondence. It also introduces a new property: there is an
event horizon candidate in close proximity to any slowly evolving horizon.Comment: 19 pages, 2 figures, will appear as a chapter of "Black Holes: New
Horizons" edited by S. Haywar
Canonical Phase Space Formulation of Quasilocal General Relativity
We construct a Hamiltonian formulation of quasilocal general relativity using
an extended phase space that includes boundary coordinates as configuration
variables. This allows us to use Hamiltonian methods to derive an expression
for the energy of a non-isolated region of space-time that interacts with its
neighbourhood. This expression is found to be very similar to the Brown-York
quasilocal energy that was originally derived by Hamilton-Jacobi methods. We
examine the connection between the two formalisms and find that when the
boundary conditions for the two are harmonized, the resulting quasilocal
energies are identical.Comment: 31 pages, 2 figures, references added, typos corrected, section 3
revised for clarity, to appear in Classical and Quantum Gravit
- …