61 research outputs found
An extension of Birkhoff's theorem to a class of 2-d gravity theories containing black holes
A class of 2-dimensional models including 2-d dilaton gravity, spherically
symmetric reduction of d-dimensional Einstein gravity and other related
theories are classically analyzed. The general analytic solutions in the
absence of matter fields other than a U(1) gauge field are obtained under a new
gauge choice and recast in the conventional conformal gauge. These solutions
imply that Birkhoff's theorem, originally applied to spherically symmetric 4-d
Einstein gravity, can be applied to all models we consider. Some issues related
to the coupling of massless scalar fields and the quantization are briefly
discussed.Comment: 11 pages, PUPT-142
Anatomy of One-Loop Effective Action in Noncommutative Scalar Field Theories
One-loop effective action of noncommutative scalar field theory with cubic
self-interaction is studied. Utilizing worldline formulation, both planar and
nonplanar part of the effective action are computed explicitly. We find
complete agreement of the result with Seiberg-Witten limit of string worldsheet
computation and standard Feynman diagrammatics. We prove that, at low-energy
and large noncommutativity limit, nonplanar part of the effective action is
simplified enormously and is resummable into a quadratic action of scalar open
Wilson line operators.Comment: 26 pages, Latex, 4 eps figures, v2. typos corrected, v3.
combinatorics correcte
Exactly solvable charged dilaton gravity theories in two dimensions
We find exactly solvable dilaton gravity theories containing a U(1) gauge
field in two dimensional space-time. The classical general solutions for the
gravity sector (the metric plus the dilaton field) of the theories coupled to a
massless complex scalar field are obtained in terms of the stress-energy tensor
and the U(1) current of the scalar field. We discuss issues that arise when we
attempt to use these models for the study of the gravitational back-reaction.Comment: The introductory part is changed. a version to appear in Class.
Quant. Grav. 6 pages, RevTe
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