3 research outputs found
A Positivity Theorem for Gravitational Tension in Brane Spacetimes
We study transverse asymptotically flat spacetimes without horizons that
arise from brane matter sources. We assume that asymptotically there is a
spatial translation Killing vector that is tangent to the brane. Such
spacetimes are characterized by a tension, analogous to the ADM mass, which is
a gravitational charge associated with the asymptotic spatial translation
Killing vector. Using spinor techniques, we prove that the purely gravitational
contribution to the spacetime tension is positive definite.Comment: 8+1 page
Tension Perturbations of Black Brane Spacetimes
We consider black-brane spacetimes that have at least one spatial translation
Killing field that is tangent to the brane. A new parameter, the tension of a
spacetime, is defined. The tension parameter is associated with spatial
translations in much the same way that the ADM mass is associated with the time
translation Killing field. In this work, we explore the implications of the
spatial translation symmetry for small perturbations around a background black
brane. For static charged black branes we derive a law which relates the
tension perturbation to the surface gravity times the change in the the horizon
area, plus terms that involve variations in the charges and currents. We find
that as a black brane evaporates the tension decreases. We also give a simple
derivation of a first law for black brane spacetimes. These constructions hold
when the background stress-energy is governed by a Hamiltonian, and the results
include arbitrary perturbative stress-energy sources.Comment: 21 pages, o figures, harvma
New Phase Diagram for Black Holes and Strings on Cylinders
We introduce a novel type of phase diagram for black holes and black strings
on cylinders. The phase diagram involves a new asymptotic quantity called the
relative binding energy. We plot the uniform string and the non-uniform string
solutions in this new phase diagram using data of Wiseman. Intersection rules
for branches of solutions in the phase diagram are deduced from a new Smarr
formula that we derive.Comment: 19 pages, 6 figures, v2: typos corrected, v3: refs. added, comment on
bounds on the relative binding energy n added in end of section