188 research outputs found
Kodaira-Spencer Theory of Gravity and Exact Results for Quantum String Amplitudes
We develop techniques to compute higher loop string amplitudes for twisted
theories with (i.e. the critical case). An important
ingredient is the discovery of an anomaly at every genus in decoupling of BRST
trivial states, captured to all orders by a master anomaly equation. In a
particular realization of the theories, the resulting string field theory
is equivalent to a topological theory in six dimensions, the Kodaira--Spencer
theory, which may be viewed as the closed string analog of the Chern--Simon
theory. Using the mirror map this leads to computation of the `number' of
holomorphic curves of higher genus curves in Calabi--Yau manifolds. It is shown
that topological amplitudes can also be reinterpreted as computing corrections
to superpotential terms appearing in the effective 4d theory resulting from
compactification of standard 10d superstrings on the corresponding
theory. Relations with strings are also pointed out.Comment: 178 pages, 20 figure
The Asymptotic Dynamics of de Sitter Gravity in three Dimensions
We show that the asymptotic dynamics of three-dimensional gravity with
positive cosmological constant is described by Euclidean Liouville theory. This
provides an explicit example of a correspondence between de Sitter gravity and
conformal field theories. In the case at hand, this correspondence is
established by formulating Einstein gravity with positive cosmological constant
in three dimensions as an SL(2,C) Chern-Simons theory. The de Sitter boundary
conditions on the connection are divided into two parts. The first part reduces
the CS action to a nonchiral SL(2,C) WZNW model, whereas the second provides
the constraints for a further reduction to Liouville theory, which lives on the
past boundary of dS_3.Comment: 12 pages, LaTeX, no figures, v2: Minor changes, references adde
I-Brane Inflow and Anomalous Couplings on D-Branes
We show that the anomalous couplings of -brane gauge and gravitational
fields to Ramond-Ramond tensor potentials can be deduced by a simple anomaly
inflow argument applied to intersecting -branes and use this to determine
the eight-form gravitational coupling.Comment: 8 pages, harvmac, no figure
Dualities in integrable systems and N=2 theories
We discuss dualities of the integrable dynamics behind the exact solution to
the N=2 SUSY YM theory. It is shown that T duality in the string theory is
related to the separation of variables procedure in dynamical system. We argue
that there are analogues of S duality as well as 3d mirror symmetry in the
many-body systems of Hitchin type governing low-energy effective actions.Comment: 16 pages, Latex, Talk given at QFTHEP-99, Moscow, May 27-June
Extended N=2 Superconformal Structure of Gravity and W-Gravity Coupled to Matter
We show that almost all string theories, including the bosonic string, the
superstring and -string theories, possess a twisted N=2 superconformal
symmetry. This enables us to establish a connection between topological gravity
and the field theoretical description of matter coupled to gravity. We also
show how the \brs operators of the -string can be obtained by hamiltonian
reduction of . The tachyonic and ground ring states of -strings
are described in the light of the N=2 superconformal structure, and the ground
ring generators for the non-critical -string are explicitly constructed.
The relationship to models and quantum integrable systems is also briefly
described.Comment: 48 page
Holonomy from wrapped branes
Compactifications of M-theory on manifolds with reduced holonomy arise as the
local eleven-dimensional description of D6-branes wrapped on supersymmetric
cycles in manifolds of lower dimension with a different holonomy group.
Whenever the isometry group SU(2) is present, eight-dimensional gauged
supergravity is a natural arena for such investigations. In this paper we use
this approach and review the eleven dimensional description of D6-branes
wrapped on coassociative 4-cycles, on deformed 3-cycles inside Calabi-Yau
threefolds and on Kahler 4-cycles.Comment: 1+8 pages, Latex. Proceedings of the Leuven workshop, 2002. v2:
Corrected typos in equations (4)-(8
An Introduction to Extra Dimensions
Models that involve extra dimensions have introduced completely new ways of
looking up on old problems in theoretical physics. The aim of the present notes
is to provide a brief introduction to the many uses that extra dimensions have
found over the last few years, mainly following an effective field theory point
of view. Most parts of the discussion are devoted to models with flat extra
dimensions, covering both theoretical and phenomenological aspects. We also
discuss some of the new ideas for model building where extra dimensions may
play a role, including symmetry breaking by diverse new and old mechanisms.
Some interesting applications of these ideas are discussed over the notes,
including models for neutrino masses and proton stability. The last part of
this review addresses some aspects of warped extra dimensions, and graviton
localization.Comment: 39 pages. Two figures. Comments and references added. Lectures given
at the XI Mexican School of Particles and Fields. Xalapa, Mexico, August
1-13, 200
On the Classical Algebra
We consider the classical \w42 algebra from the integrable system viewpoint.
The integrable evolution equations associated with the \w42 algebra are
constructed and the Miura maps , consequently modifications, are presented.
Modifying the Miura maps, we give a free field realization the classical \w42
algebra. We also construct the Toda type integrable systems for it.Comment: 14 pages, latex, no figure
New Spinor Field Realizations of the Non-Critical String
We investigate the new spinor field realizations of the algebra,
making use of the fact that the algebra can be linearized by the
addition of a spin-1 current. We then use these new realizations to build the
nilpotent Becchi-Rouet-Stora--Tyutin (BRST) charges of the spinor non-critical
string.Comment: 8 pages, no figures, revtex4 style, accepted by Chin. Phys. Let
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