265 research outputs found
Geometric Construction of AdS Twistors
Time-like geodesics in AdS_4, AdS_5 and AdS_7 are constructed geometrically
and independently of choice of AdS coordinates from division algebra spinors of
the corresponding AdS groups, explaining and generalising the construction by
Claus et al. of AdS_5 twistors.Comment: 11 pp, 1 figur
Superspace Methods in String Theory, Supergravity and Gauge Theory
In these two lectures, delivered at the XXXVII Karpacz Winter School,
February 2001, I review some applications of superspace in various topics
related to string theory and M-theory. The first lecture is mainly devoted to
descriptions of brane dynamics formulated in supergravity backgrounds. The
second lecture concerns the use of superspace techniques for determining
consistent interactions in supersymmetric gauge theory and supergravity, e.g.
alpha'-corrections from string/M-theory.Comment: 15 pp., latex, aippro
Boundaries of 11-Dimensional Membranes
The action for an 11-dimensional supermembrane contains a chiral
Wess-Zumino-Witten model coupling to the E8 super-Yang-Mills theory on the
end-of-the-world 9-brane. It is demonstrated that this boundary string theory
is dictated both by gauge invariance and by kappa-symmetry.Comment: plain tex, 6p
Non-gravitational exceptional supermultiplets
We examine non-gravitational minimal supermultiplets which are based on the
tensor gauge fields appearing as matter fields in exceptional generalised
geometry. When possible, off-shell multiplets are given. The fields in the
multiplets describe non-gravitational parts of the internal dynamics of
compactifications of M-theory. In flat backgrounds, they enjoy a global
U-duality symmetry, but also provide multiplets with a possibility of coupling
to a generalised exceptional geometry.Comment: 11 pp., plain te
World-volume fields and background coupling of branes
This is the written version of an invited talk delivered at the workshop
``Quantum gravity in the Southern Cone'' held in San Carlos de Bariloche,
Argentina, January 7-10, 1998. After giving a brief introduction to the concept
of branes and their role in string theory, this talk describes a method for
formulating the dynamics of branes, especially those containing non-scalar
moduli. Emphasis is put on the coupling of branes to fields in the low-energy
background supergravity theories, and on preservation of maximal amount of
manifest symmetry. Due to the nature of the workshop, the presentation is aimed
at physicists who are not experts in string theory.Comment: 12 pp, plain tex, talk presented at the workshop ``Quantum gravity in
the Southern Cone'' held in San Carlos de Bariloche, Argentina, January 7-10,
199
Thoughts on Membranes, Matrices and Non-Commutativity
We review the passage from the supermembrane to matrix theory via a
consistent truncation following a non-commutative deformation in light-cone
gauge. Some indications are given that there should exist a generalisation of
non-commutativity involving a three-index theta on the membrane, and we discuss
some possible ways of investigating the corresponding algebraic structure.Comment: 11 pp, plain tex. Invited talk presented at the conference
``Non-Commutative Geometry and Representation Theory in Mathematical
Physics'', Karlstad, Sweden, July 5-10, 200
M-branes on U-folds
We give a preliminary discussion of how the addition of extra coordinates in
M-theory, which together with the original ones parametrise a U-fold, can serve
as a tool for formulating brane dynamics with manifest U-duality. The redundant
degrees of freedom are removed by generalised self-duality constraints or
calibration conditions made possible by the algebraic structure of U-duality.
This is the written version of an invited talk at the 7th International
Workshop "Supersymmetries and Quantum Symmetries", Dubna, July 30-August 4,
2007.Comment: 8 p
as space-time symmetry --- Origin of the twistor transform
Massless particle dynamics in Minkowski space is given an
-covariant formulation, including both space-time and twistor variables.
contains the conformal algebra as a subalgebra. Analogous constructions
apply to and 6.Comment: 4 page
Problems with Duality in N=2 Super-Yang-Mills Theory
Actual calculations of monopole and dyon spectra have previously been
performed in N=4 SYM and in N=2 SYM with gauge group SU(2), and are in total
agreement with duality conjectures for the finite theories. These calculations
are extended to N=2 SYM with higher rank gauge groups, and it turns out that
the SU(2) model with four fundamental hypermultiplet is an exception in that
its soliton spectrum supports duality. This may be an indication that the other
perturbatively finite N=2 theories have non-perturbative contributions to the
beta-function. This talk contains a short summary of recent results.Comment: 5 pp., plain tex. Talk presented at the Second International Sakharov
Conference on Physics, Moscow, May 199
Pure spinor superfields, with application to D=3 conformal models
I review and discuss the construction of supersymmetry multiplets and
manifestly supersymmetric Batalin-Vilkovisky actions using pure spinors, with
emphasis on models with maximal supersymmetry. The special cases of D=3, N=8
(Bagger-Lambert-Gustavsson) and N=6 (Aharony-Bergman-Jafferis-Maldacena)
conformal models are treated in detail. Most of the material is covered by the
papers arXiv:0808.3242 and arXiv:0809.0318. This is the written version of a
talk given at 4th Baltic-Nordic workshop "Algebra, Geometry and Mathematical
Physics", Tartu, Estonia, October 9-11, 2008, to appear in the Proceedings of
the Estonian Academy of Sciences, vol 4, 2010.Comment: 13 p
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