55 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
One-loop Noncommutative U(1) Gauge Theory from Bosonic Worldline Approach
We develop a method to compute the one-loop effective action of
noncommutative U(1) gauge theory based on the bosonic worldline formalism, and
derive compact expressions for N-point 1PI amplitudes. The method, resembling
perturbative string computations, shows that open Wilson lines emerge as a
gauge invariant completion of certain terms in the effective action. The terms
involving open Wilson lines are of the form reminiscent of closed string
exchanges between the states living on the two boundaries of a cylinder. They
are also consistent with recent matrix theory analysis and the results from
noncommutative scalar field theories with cubic interactions.Comment: 1+35 pages, Latex, address info adde
- …