{ital U} duality, {ital D}-branes, and black hole emission rates: Agreements and disagreements
- Blackett Laboratory, Imperial College of Science, Technology and Medicine, London SW7 2BZ (United Kingdom)
- Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003-4525 (United States)
An expression for the spacetime absorption coefficient of a scalar field in a five-dimensional, near-extremal black hole background is derived, which has the same form as that presented by Maldacena and Strominger, but is valid over a larger, {ital U}-duality invariant region of parameter space and in general disagrees with the corresponding {ital D}-brane result. We develop an argument, based on {ital D}-brane thermodynamics, which specifies the range of parameters over which agreement should be expected. For neutral emission, the spacetime and {ital D}-brane results agree over this range. However, for charged emission, we find disagreement in the {open_quotes}fat black hole{close_quotes} regime, in which charge is quantized in smaller units on the brane than in the bulk of spacetime. We indicate a possible problem with the {ital D}-brane model in this regime. We also use the Born approximation to study the high frequency limit of the absorption coefficient and find that it approaches unity, for large black hole backgrounds, at frequencies still below the string scale, again in disagreement with {ital D}-brane results. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 670269
- Journal Information:
- Physical Review, D, Vol. 58, Issue 12; Other Information: PBD: Dec 1998
- Country of Publication:
- United States
- Language:
- English
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