138 research outputs found
Radiation equations for black holes
It has been shown in the previous paper that the metric in the semiclassical
region of the collapse spacetime is expressed purely kinematically through the
Bondi charges. Here the Bondi charges are expressed through this metric by
calculating the vacuum radiation against its background. The result is closed
equations for the metric and the Bondi charges. Notably, there is a
nonvanishing flux of the vacuum-induced matter charge.Comment: 16 pages, 1 figure. Latex 2.09. Figure PN
The vacuum backreaction on a pair creating source
Solution is presented to the simplest problem about the vacuum backreaction
on a pair creating source. The backreaction effect is nonanalytic in the
coupling constant and restores completely the energy conservation law. The
vacuum changes the kinematics of motion like relativity theory does and imposes
a new upper bound on the velocity of the source.Comment: 9 pages including 2 figures. Latex 2.09. Figures by Metafont, 300
dpi. Keep all files in a separate director
On electrodynamics of rapidly moving sources
Rapidly moving sources create pairs in the vacuum and lose energy. In consequence of this, the velocity of a charged body cannot approach the speed of light closer than a certain limit which depends only on the coupling constant. The vacuum back-reaction secures the observance of the conservation laws. A source can lose up to 50% of energy and charge because of the vacuum instability
The basis of nonlocal curvature invariants in quantum gravity theory
A complete basis of nonlocal invariants in quantum gravity theory is built to
third order in spacetime curvature and matter-field strengths. The nonlocal
identities are obtained which reduce this basis for manifolds with
dimensionality . The present results are used in heat-kernel theory,
theory of gauge fields and serve as a basis for the model-independent approach
to quantum gravity and, in particular, for the study of nonlocal vacuum effects
in the gravitational collapse problem.Comment: 28 pages, REVTeX, Alberta Thy 14-9
Conformal invariance and apparent universality of semiclassical gravity
In a recent work, it has been pointed out that certain observables of the
massless scalar field theory in a static spherically symmetric background
exhibit a universal behavior at large distances. More precisely, it was shown
that, unlike what happens in the case the coupling to the curvature \xi is
generic, for the special cases \xi=0 and \xi = 1/6 the large distance behavior
of the expectation value turns out to be independent of the
internal structure of the gravitational source. Here, we address a higher
dimensional generalization of this result: We first compute the difference
between a black hole and a static spherically symmetric star for the
observables and in the far field limit. Thus, we show
that the conformally invariant massless scalar field theory in a static
spherically symmetric background exhibits such universality phenomenon in D\geq
4 dimensions. Also, using the one-loop effective action, we compute
for a weakly gravitating object. These results lead to the
explicit expression of the expectation value for a
Schwarzschild-Tangherlini black hole in the far field limit. As an application,
we obtain quantum corrections to the gravitational potential in D dimensions,
which for D=4 are shown to agree with the one-loop correction to the graviton
propagator previously found in the literature.Comment: 11 page
Geodesics, gravitons and the gauge fixing problem
When graviton loops are taken into account, the background metric obtained as
a solution to the one-loop corrected Einstein equations turns out to be gauge
fixing dependent. Therefore it is of no physical relevance. Instead we consider
a physical observable, namely the trajectory of a test particle in the presence
of gravitons. We derive a quantum corrected geodesic equation that includes
backreaction effects and is explicitly independent of any gauge fixing
parameter.Comment: 21 pages, no figures, RevTe
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