247 research outputs found
TASI Lectures: Particle Physics from Perturbative and Non-perturbative Effects in D-braneworlds
In these notes we review aspects of semi-realistic particle physics from the
point of view of type II orientifold compactifications. We discuss the
appearance of gauge theories on spacetime filling D-branes which wrap
non-trivial cycles in the Calabi-Yau. Chiral matter can appear at their
intersections, with a natural interpretation of family replication given by the
topological intersection number. We discuss global consistency, including
tadpole cancellation and the generalized Green-Schwarz mechanism, and also the
importance of related global symmetries for superpotential couplings. We
review the basics of D-instantons, which can generate superpotential
corrections to charged matter couplings forbidden by the global
symmetries and may play an important role in moduli stabilization. Finally, for
the purpose of studying the landscape, we discuss certain advantages of
studying quiver gauge theories which arise from type II orientifold
compactifications rather than globally defined models. We utilize the type IIa
geometric picture and CFT techniques to illustrate the main physical points,
though sometimes we supplement the discussion from the type IIb perspective
using complex algebraic geometry.Comment: 35 pages. Based on lectures given by M.C. at TASI 2010. v2: added
references, fixed typo
BPS Saturated and Non-Extreme States in Abelian Kaluza-Klein Theory and Effective N=4 Supersymmetric String Vacua
We summarize results for all four-dimensional Bogomol'nyi-Sommerfield-Prasat
(BPS) saturated and non-extreme solutions of the ()-dimensional Abelian
Kaluza-Klein theory. Within effective N=4 supersymmetric string vacua,
parameterized in terms of fields of the heterotic string on a six-torus, we
then present a class of BPS saturated states and the corresponding non-extreme
solutions, specified by and orbits of general dyonic
charge configurations with zero axion. The BPS saturated states with
non-negative norms for electric and magnetic charge vectors, along
with the corresponding set of non-extreme solutions, are regular with non-zero
masses. BPS saturated states with the negative charge norms are singular,
unaccompanied by non-extreme solutions and become massless at particular points
of the moduli space. The role that such massless states may play in the
enhancement of non-Abelian gauge symmetry as well as local supersymmetry is
addressed.Comment: 18 pages, uses RevTex, contribution to the Proceedings of String'95
conferenc
Wave Equation for the Wu Black Hole
Wu black hole is the most general solution of maximally supersymmetric gauged
supergravity in D=5, containing gauge symmetry. We study the
separability of the massless Klein-Gordon equation and probe its singularities
for a general stationary, axisymmetric metric with orthogonal transitivity, and
apply the results to the Wu black hole solution. We start with the zero
azimuthal-angle eigenvalues in the scalar field Ansatz and find that the
residuum of a pole in the radial equation is associated with the surface
gravity calculated at this horizon. We then generalize our calculations to
nonzero azimuthal eigenvalues and probing each horizon singularity, we show
that the residua of the singularities for each horizon are in general
associated with a specific combination of the surface gravity and the angular
velocities at the associated horizon. It turns out that for the Wu black hole
both the radial and angular equations are general Heun's equations with four
regular singularities.Comment: 19 pages, minor corrections and reference added. Matches the
published versio
Supersymmetric Domain-Wall World from D=5 Simple Gauged Supergravity
We address a supersymmetric embedding of domain walls with asymptotically
anti-deSitter (AdS) space-times in five-dimensional simple, N=2 U(1) gauged
supergravity theory constructed by Gunaydin, Townsend and Sierra. These
conformally flat solutions interpolate between supersymmetric AdS vacua,
satisfy the Killing spinor (first order) differential equations, and the
four-dimensional world on the domain wall is a flat world with N=1
supersymmetry. Regular solutions in this class have the energy density related
to the cosmological constants of the supersymmetric AdS vacua. An analysis of
such solutions is given for the example of one (real, neutral) vector
supermultiplet with the most general form of the prepotential. There are at
most two supersymmetric AdS vacua that are in general separated by a
singularity in the potential. Nevertheless the supersymmetric domain wall
solution exists with the scalar field interpolating continuously across the
singular region.Comment: 12 pages, LaTeX, sign corrected, resulting in a different asymptotics
for the exampl
Extreme Domain Wall--Black Hole Complementarity in N=1SUPERGRAVITY with a General Dilaton Coupling
We study supersymmetric (extreme) domain walls in four-dimensional (4d) N=1
supergravity theories with a general dilaton coupling . Type I
walls, which are static, planar (say, in () plane) configurations,
interpolate between Minkowski space-time and a vacuum with a varying dilaton
field. We classify their global space-time with respect to the value of the
coupling . supergravity with , an effective theory
from superstrings, provides a dividing line between the theories with
, where there is a naked (planar) singularity on one side of the
wall, and the theories with , where the singularity of the of the
wall is covered by the horizon. The global space-time (in ) direction) of
the extreme walls with the coupling is the same as the global
space-time (in ( direction) of the extreme magnetically charged black
holes with the coupling .Comment: 11 pages (3 figures available from
ftp://dept.physics.upenn.edu/pub/UPR-600-T/), UPR-600-T revised to be
compatible with the published versio
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