59 research outputs found
Perturbative Chern-Simons Theory From The Penner Model
We show explicitly that the perturbative SU(N) Chern-Simons theory arises
naturally from two Penner models, with opposite coupling constants. As a result
computations in the perturbative Chern-Simons theory are carried out using the
Penner model, and it turns out to be simpler and transparent. It is also shown
that the connected correlators of the puncture operator in the Penner model,
are related to the connected correlators of the operator that gives the Wilson
loop operator in the conjugacy class.Comment: 7 Pages, Published Versio
S-duality and Topological Strings
In this paper we show how S-duality of type IIB superstrings leads to an
S-duality relating A and B model topological strings on the same Calabi-Yau as
had been conjectured recently: D-instantons of the B-model correspond to
A-model perturbative amplitudes and D-instantons of the A-model capture
perturbative B-model amplitudes.
Moreover this confirms the existence of new branes in the two models.
As an application we explain the recent results concerning A-model
topological strings on Calabi-Yau and its equivalence to the statistical
mechanical model of melting crystal.Comment: 13 page
PP-wave String Interactions from String Bit Model
We construct the string states ,
and in the Hilbert space of the quantum
mechanical orbifold model so as to calculate the three point functions and the
matrix elements of the light-cone Hamiltonian from the interacting string bit
model. With these string states we show that the three point functions and the
matrix elements of the Hamiltonian derived from the interacting string bit
model up to order precisely match with those computed from the
perturbative SYM theory in BMN limit.Comment: 20 pages, no figure, LaTeX, some changes made and references adde
Orientifolds of type IIA strings on Calabi-Yau manifolds
We identify type IIA orientifolds that are dual to M-theory compactifications
on manifolds with G_2-holonomy. We then discuss the construction of crosscap
states in Gepner models. (Based on a talk presented by S.G. at PASCOS 2003 held
at the Tata Institute of Fundamental Research, Mumbai during Jan. 3-8, 2003.)Comment: 3 pages, RevTeX, PASCOS '03 tal
A Weak Gravity Conjecture for Scalar Field Theories
We show that the recently proposed weak gravity conjecture\cite{AMNV0601} can
be extended to a class of scalar field theories. Taking gravity into account,
we find an upper bound on the gravity interaction strength, expressed in terms
of scalar coupling parameters. This conjecture is supported by some
two-dimensional models and noncommutative field theories.Comment: version published in JHE
Orientifold Limit of F-theory Vacua
We show how an F-theory compactified on a Calabi-Yau (n+1)-fold in
appropriate weak coupling limit reduces formally to an orientifold of type IIB
theory compactified on an auxiliary complex n-fold. In some cases (but not
always) if the original (n+1)-fold is singular, then the auxiliary n-fold is
also singular. We illustrate this by analysing F-theory on elliptically fibered
Calabi-Yau 3-folds on base .Comment: LaTeX file, 11 pages, additional argument for Calabi-Yau nature of
the auxiliary manifold, one extra referenc
NC Calabi-Yau Orbifolds in Toric Varieties with Discrete Torsion
Using the algebraic geometric approach of Berenstein et {\it al}
(hep-th/005087 and hep-th/009209) and methods of toric geometry, we study non
commutative (NC) orbifolds of Calabi-Yau hypersurfaces in toric varieties with
discrete torsion. We first develop a new way of getting complex mirror
Calabi-Yau hypersurfaces in toric manifolds with a action and analyze the general group of the
discrete isometries of . Then we build a general class of
complex dimension NC mirror Calabi-Yau orbifolds where the non
commutativity parameters are solved in terms of discrete
torsion and toric geometry data of in which the original
Calabi-Yau hypersurfaces is embedded. Next we work out a generalization of the
NC algebra for generic dimensions NC Calabi-Yau manifolds and give various
representations depending on different choices of the Calabi-Yau toric geometry
data. We also study fractional D-branes at orbifold points. We refine and
extend the result for NC to higher dimensional torii orbifolds
in terms of Clifford algebra.Comment: 38 pages, Late
Exact Superpotentials for Theories with Flavors via a Matrix Integral
We extend and test the method of Dijkgraaf and Vafa for computing the
superpotential of N=1 theories to include flavors in the fundamental
representation of the gauge group. This amounts to computing the contribution
to the superpotential from surfaces with one boundary in the matrix integral.
We compute exactly the effective superpotential for the case of gauge group
U(N_c), N_f massive flavor chiral multiplets in the fundamental and one massive
chiral multiplet in the adjoint, together with a Yukawa coupling. We compare up
to sixth-order with the result obtained by standard field theory techniques in
the already non trivial case of N_c=2 and N_f=1. The agreement is perfect.Comment: 7 pages, v2: typos involving signs fixed; v3: version to appear in
Phys.Rev.
The geometry of the limit of N=2 minimal models
We consider the limit of two-dimensional N=(2,2) superconformal minimal
models when the central charge approaches c=3. Starting from a geometric
description as non-linear sigma models, we show that one can obtain two
different limit theories. One is the free theory of two bosons and two
fermions, the other one is a continuous orbifold thereof. We substantiate this
claim by detailed conformal field theory computations.Comment: 35 pages, 3 figures; v2 minor corrections, version to be published in
J. Phys.
- …