63 research outputs found
The heterotic prepotential from eleven dimensions
We compactify M-theory in the Horava-Witten formulation on S^1/Z_2 \times K3
\times T^2. Focusing on the moduli-space of vector multiplets of the resulting
four-dimensional N=2 theory, we determine the prepotential as an expansion in
two dimensionless parameters which both scale as \kappa^{2/3}. We determine the
prepotential completely to relative order \kappa^{4/3} and compare the
expression with the results obtained for the perturbative string theories. We
find complete agreement to relative order \kappa^{4/3} between the strong and
weak coupling regimes. The sources of higher order perturbative and
non-perturbative corrections to the prepotential are also briefly discussed
from the M-theory perspective.Comment: 19 pages, LaTeX; minor change
(Super)conformal many-body quantum mechanics with extended supersymmetry
We study N=4 supersymmetric quantum-mechanical many-body systems with M
bosonic and 4M fermionic degrees of freedom. We also investigate the further
restrictions of conformal and superconformal invariance. In particular, we
construct conformal N=4 extensions of the A_{M-1} Calogero models, which for
generic values of the coupling constant are not SU(1,1|2) superconformal. This
class of models is also extended to arbitrary (even) N. We give both
hamiltonian and (classical) lagrangean formulations. In the latter case we use
both component and N=4 superfield formulations.Comment: 16 pages, LaTeX2e; minor corrections, references adde
Generalized Toda Theories from WZNW Reduction
We reconsider the, by Brink and Vasiliev, recently proposed generalized Toda
field theories using the framework of WZNWToda reduction. The
reduced theory has a gauge symmetry which can be fixed in various ways. We
discuss some different gauge choices. In particular we study the
algebra associated with the generalized model in some different realizations,
corresponding to different gauge choices. We also investigate the mapping
between the Toda field and a free field and show the relation between the
algebra generators expressed in terms of the two different fields.
All results apply also to the case of ordinary Toda theories.Comment: 18 pages, Plain LaTe
A note on S-duality for the N=1* Sp(2n) and SO(2n+1) super-Yang-Mills theories
We study the N=1* supersymmetric gauge theories with gauge groups Sp(2n) and
SO(2n+1). These theories are obtained from the corresponding N=4 supersymmetric
Yang-Mills theories via a mass deformation. We show that the number of quantum
vacua in the Sp(2n) theory is equal to the number of quantum vacua in the
SO(2n+1) theory. This constitutes non-trivial support for S-duality between
these theories. The verification of the equality of the number of quantum vacua
involves a rather esoteric identity due to Ramanujan.Comment: 9 pages. v2:clarifying footnote adde
Derivative corrections to the D-brane Born-Infeld action: non-geodesic embeddings and the Seiberg-Witten map
We dimensionally reduce the four-derivative corrections to the
parity-conserving part of the D9-brane effective action involving all orders of
the gauge field, to obtain corrections to the actions for the lower-dimensional
Dp-branes. These corrections involve the second fundamental form and correspond
to a non-geodesic embedding of the Dp-brane into (flat) ten-dimensional space.
In addition, we study the transformation of the corrections under the
Seiberg-Witten map relating the ordinary and non-commutative theories. A
speculative discussion about the higher-order terms in the derivative expansion
is also included.Comment: 20 pages, LaTeX. v2: relation between (2.11) and result in
hep-th/9903210 clarified. v3: minor changes; reference adde
Towards a manifestly SL(2,Z)-covariant action for the type IIB (p,q) super-five-branes
We determine a manifestly SL(2,Z)-covariant kappa-symmetric action for the
type IIB (p,q) five-branes as a perturbative expansion in the world-volume
field strengths within the framework where the brane tension is generated by a
world-volume field. In this formulation the Lagrangian is expected to be
polynomial; we construct the kappa-invariant action to fourth order in the
world-volume field strengths.Comment: 9 pages, LaTeX2
Towards relating the kappa-symmetric and pure-spinor versions of the supermembrane
We study the relation between the kappa-symmetric formulation of the
supermembrane in eleven dimensions and the pure-spinor version. Recently,
Berkovits related the Green-Schwarz and pure-spinor superstrings. In this
paper, we attempt to extend this method to the supermembrane. We show that it
is possible to reinstate the reparameterisation constraints in the pure-spinor
formulation of the supermembrane by introducing a topological sector and
performing a similarity transformation. The resulting BRST charge is then of
conventional type and is argued to be (related to) the BRST charge of the
kappa-symmetric supermembrane in a formulation where all second class
constraints are 'gauge unfixed' to first class constraints. In our analysis we
also encounter a natural candidate for a (non-covariant) supermembrane analogue
of the superstring b ghost.Comment: 15 Page
An A_r threesome: Matrix models, 2d CFTs and 4d N=2 gauge theories
We explore the connections between three classes of theories: A_r quiver
matrix models, d=2 conformal A_r Toda field theories and d=4 N=2 supersymmetric
conformal A_r quiver gauge theories. In particular, we analyse the quiver
matrix models recently introduced by Dijkgraaf and Vafa and make detailed
comparisons with the corresponding quantities in the Toda field theories and
the N=2 quiver gauge theories. We also make a speculative proposal for how the
matrix models should be modified in order for them to reproduce the instanton
partition functions in quiver gauge theories in five dimensions.Comment: 43 pages; v2: minor typos corrected, reference added. v3: Added
clarifying discussions in sections 4.1 and 5.1; typos correcte
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