MG11 
Talk detail
 

 Participant 

Institution

Session

Talk

Abstract

Hawking Radiation and Black Hole Thermodynamics

A brief review of Hawking radiation and black hole thermodynamics will be given, based mainly upon hep-th/0409024, including a discussion of the ambiguities of defining logarithmic terms in the black hole entropy, and possibly adding some discussion of the thermodynamics of nearly extremal black holes, based upon hep-th/0409024.

Boundary Conditions and Predictions of Quantum Cosmology

A brief summary will be given of some of the conceptual issues of boundary conditions and predictions of quantum cosmology, including the severe problem that Susskind has raised with the Hartle-Hawking no-boundary proposal in the presence of a cosmological constant or dark energy (predicting that the present universe should be thermal with the Gibbons-Hawking de Sitter temperature, a problem which I believe remains even within the "top down" approach of Hawking and Hertog, hep-th/0602091).

No Astrophysical Dyadospheres

Ruffini and his collaborators have proposed a model for gamma ray bursts that invokes a `dyadosphere,' a macroscopic region of spacetime with rapid Schwinger pair production, where the electric field exceeds the critical electric field value m^2/e (with electron mass m and charge -e). Here it is shown how pair production itself would prevent the astrophysical formation of dyadospheres. Pair production is a self-regulating process that would discharge a growing electric field (say from a hypothetical collapsing charged stellar core) before it reached 6% of the minimum dyadosphere value, keeping the pair production rate more than 26 orders of magnitude below the dyadosphere value, and the efficiency well below 0.1%.