7 research outputs found
Low-energy sector quantization of a massless scalar field outside a Reissner-Nordstrom black hole and static sources
We quantize the low-energy sector of a massless scalar field in the
Reissner-Nordstrom spacetime. This allows the analysis of processes involving
soft scalar particles occurring outside charged black holes. In particular, we
compute the response of a static scalar source interacting with Hawking
radiation using the Unruh (and the Hartle-Hawking) vacuum. This response is
compared with the one obtained when the source is uniformly accelerated in the
usual vacuum of the Minkowski spacetime with the same proper acceleration. We
show that both responses are in general different in opposition to the result
obtained when the Reissner-Nordstrom black hole is replaced by a Schwarzschild
one. The conceptual relevance of this result is commented.Comment: 12 pages (REVTEX), no figure
Transition rate of the Unruh-DeWitt detector in curved spacetime
We examine the Unruh-DeWitt particle detector coupled to a scalar field in an
arbitrary Hadamard state in four-dimensional curved spacetime. Using smooth
switching functions to turn on and off the interaction, we obtain a
regulator-free integral formula for the total excitation probability, and we
show that an instantaneous transition rate can be recovered in a suitable
limit. Previous results in Minkowski space are recovered as a special case. As
applications, we consider an inertial detector in the Rindler vacuum and a
detector at rest in a static Newtonian gravitational field. Gravitational
corrections to decay rates in atomic physics laboratory experiments on the
surface of the Earth are estimated to be suppressed by 42 orders of magnitude.Comment: 27 pages, 1 figure. v3: Typos corrected. Published versio
Scalar radiation emitted from a source rotating around a black hole
We analyze the scalar radiation emitted from a source rotating around a
Schwarzschild black hole using the framework of quantum field theory at the
tree level. We show that for relativistic circular orbits the emitted power is
about 20% to 30% smaller than what would be obtained in Minkowski spacetime. We
also show that most of the emitted energy escapes to infinity. Our formalism
can readily be adapted to investigate similar processes.Comment: 19 pages (REVTEX), 5 figures, title slightly changed, extra
demonstration and minor improvements included. To appear in Class. Quant.
Gra
Accelerating Branes and Brane Temperature
We define the local acceleration and jerk of a relativistic brane in an
ambient spacetime, and construct from them a dimensionless parameter lambda
that must be small for an interpretation of brane acceleration as local Unruh
temperature. As examples, we discuss (i) open rotating branes, for which
lambda>1 (ii) closed spherical branes expanding in Minkowski spacetime, for
which lambda=0 when the worldvolume is either an Einstein static universe or de
Sitter space, in which case the brane temperature equals the Gibbons-Hawking
temperature, (iii) closed spherical branes in anti-de Sitter spacetime, for
which a maximally symmetric worldvolume is anti-de Sitter, Minkowski or de
Sitter according to whether the magnitude of the brane acceleration is less
than, equal to or greater than a `critical' value, and (iv) the BTZ black hole,
viewed as a membrane.Comment: 32 pages, small correction
Quantization of the electromagnetic field outside static black holes and its application to low-energy phenomena
We discuss the Gupta-Bleuler quantization of the free electromagnetic field outside static black holes in the Boulware vacuum. We use a gauge which reduces to the Feynman gauge in Minkowski spacetime. We also discuss its relation with gauges used previously. Then we apply the low-energy sector of this field theory to investigate some low-energy phenomena. First, we discuss the response rate of a static charge outside the Schwarzschild black hole in four dimensions. Next, motivated by string physics, we compute the absorption cross sections of low-energy plane waves for the Schwarzschild and extreme Reissner-Nordström black holes in arbitrary dimensions higher than three