823 research outputs found
Coset Character Identities in Superstring Compactifications
We apply the coset character identities (generalization of Jacobi's abstruse
identity) to compact and noncompact Gepner models. In the both cases, we prove
that the partition function actually vanishes due to the spacetime
supersymmetry. In the case of the compact models and discrete parts of the
noncompact models, the partition function includes the expected vanishing
factor. But the character identities used to the continuous part of the
noncompact models suggest that these models have twice as many supersymmetry as
expected. This fact is an evidence for the conjecture that the holographically
dual of the string theory on an actually singular Calabi-Yau manifold is a
super CONFORMAL field theory. The extra SUSY charges are interpreted as the
superconformal S generators.Comment: 23 pages, LaTeX, no figure. v2:corrected typos, added detailed
calculations, added references. v3:corrected typo
A Change of Variables to the Dual and Factorization of Composite Anomalous Jacobians
Changes of variables giving the dual model are constructed explicitly for
sigma-models without isotropy. In particular, the jacobian is calculated to
give the known results. The global aspects of the abelian case as well as some
of those of the cases where the isometry group is simply connected are
considered.
Considering the anomalous case, we infer by a consistency argument that the
`multiplicative anomaly' should be replaceable by adequate rules for
factorization of composite jacobians. These rules are then generalized in a
simple way for composite jacobians defined in spaces of different types.
Implimentation of these rules then gives specific formulas for the anomally for
semisimple algebras and also for solvable ones.Comment: 15 pages, no figures, Latex file, A treatment of the global aspects
of the abelian and of semisimple duality groups are added. General formulas
for the mixed anomaly are derive
Type 0 Strings in a 2-d Black Hole
We study some aspects of type 0 strings propagating in the two dimensional
black hole geometry, corresponding to the exact SL(2)/U(1) SCFT background.Comment: 33 pages, harvmac. v2: minor clarification adde
Beyond the Singularity of the 2-D Charged Black Hole
Two dimensional charged black holes in string theory can be obtained as exact
(SL(2,R)xU(1))/U(1) quotient CFTs. The geometry of the quotient is induced from
that of the group, and in particular includes regions beyond the black hole
singularities. Moreover, wavefunctions in such black holes are obtained from
gauge invariant vertex operators in the SL(2,R) CFT, hence their behavior
beyond the singularity is determined. When the black hole is charged we find
that the wavefunctions are smooth at the singularities. Unlike the uncharged
case, scattering waves prepared beyond the singularity are not fully reflected;
part of the wave is transmitted through the singularity. Hence, the physics
outside the horizon of a charged black hole is sensitive to conditions set
behind the past singularity.Comment: 19 pages, 5 figures; v2: refs added, minor typos corrected; v3:
references on the infinite blue shift at the inner horizon and minor
corrections adde
Non-critical Heterotic Superstrings in Various Dimensions
We construct heterotic string theories on spacetimes of the form R^{d-1,1}
times N=2 linear dilaton, where d=6,4,2,0. There are two lines of
supersymmetric theories descending from the two supersymmetric ten-dimensional
heterotic theories. These have gauge groups which are lower rank subgroups of
E_{8} times E_{8} and SO(32). On turning on a (2,2) deformation which makes the
two dimensional part a smooth SL_{2}(R)/U(1) supercoset, the gauge groups get
broken further. In the deformed theories, there are non-trivial moduli which
are charged under the surviving gauge group in the case of d=6. We construct
the marginal operators on the worldsheet corresponding to these moduli.Comment: 27 pages, harvmac. v2 reference adde
IIA Perspective On Cascading Gauge Theory
We study the N=1 supersymmetric cascading gauge theory found in type IIB
string theory on p regular and M fractional D3-branes at the tip of the
conifold, using the T-dual type IIA description. We reproduce the
supersymmetric vacuum structure of this theory, and show that the IIA analog of
the non-supersymmetric state found by Kachru, Pearson and Verlinde in the IIB
description is metastable in string theory, but the barrier for tunneling to
the supersymmetric vacuum goes to infinity in the field theory limit. We also
comment on the N=2 supersymmetric gauge theory corresponding to regular and
fractional D3-branes on a near-singular K3, and clarify the origin of the
cascade in this theory.Comment: 43 pages, 18 figures, harvma
Target Space Duality between Simple Compact Lie Groups and Lie Algebras under the Hamiltonian Formalism: I. Remnants of Duality at the Classical Level
It has been suggested that a possible classical remnant of the phenomenon of
target-space duality (T-duality) would be the equivalence of the classical
string Hamiltonian systems. Given a simple compact Lie group with a
bi-invariant metric and a generating function suggested in the physics
literature, we follow the above line of thought and work out the canonical
transformation generated by together with an \Ad-invariant
metric and a B-field on the associated Lie algebra of so that
and form a string target-space dual pair at the classical level under
the Hamiltonian formalism. In this article, some general features of this
Hamiltonian setting are discussed. We study properties of the canonical
transformation including a careful analysis of its domain and image. The
geometry of the T-dual structure on is lightly touched.Comment: Two references and related comments added, also some typos corrected.
LaTeX and epsf.tex, 36 pages, 4 EPS figures included in a uuencoded fil
Comments on D-branes in Kazama-Suzuki models and Landau-Ginzburg theories
We study D-branes in Kazama-Suzuki models by means of the boundary state
description. We can identify the boundary states of Kazama-Suzuki models with
the solitons in N=2 Landau-Ginzburg theories. We also propose a geometrical
interpretation of the boundary states in Kazama-Suzuki models.Comment: 28 pages, 2 figure
Free field realization of superstring theory on AdS3
The Coulomb gas representation of expectation values in SU(2) conformal field
theory developed by Dotsenko is extended to the SL(2,R) WZW model and applied
to bosonic string theory on AdS3 and to Type II superstrings on AdS3 x N. The
spectral flow symmetry is included in the free field realization of vertex
operators creating superstring states of both Ramond and Neveu-Schwarz sectors.
Conjugate representations for these operators are constructed and a background
charge prescription is designed to compute correlation functions. Two and three
point functions of bosonic and fermionic string states in arbitrary winding
sectors are calculated. Scattering amplitudes that violate winding number
conservation are also discussed.Comment: 40 pages, typos corrected, references added, minor changes in
presentation and details completed in the calculation of the R sector 2-point
function. Version to appear in JHE
Remarks on Non-Abelian Duality
A class of two-dimensional globally scale-invariant, but not conformally
invariant, theories is obtained. These systems are identified in the process of
discussing global and local scaling properties of models related by duality
transformations, based on non-semisimple isometry groups. The construction of
the dual partner of a given model is followed through; non-local as well as
local versions of the former are discussed.Comment: 33 pages, CERN-TH.7414/94, RI-9-94, WIS-7-9
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