230 research outputs found
Partial N=2 --> N=1 Local Supersymmetry Breaking and Solvable Lie Algebras
Generic partial supersymmetry breaking of N=2 supergravity with zero vacuum
energy and with surviving unbroken arbitrary gauge groups is exhibited.
Specific examples are given.Comment: 5 pages, 1 LaTeX-style file, 1 TeX, 2 Postscript figures. Seminar
given at the Work-Shop on "Gauge Theories, Applied Supersymmetry and Quantum
Gravity", Imperial College, London, 5-10 July 199
Modular anomaly equation, heat kernel and S-duality in N=2 theories
We investigate epsilon-deformed N=2 superconformal gauge theories in four
dimensions, focusing on the N=2* and Nf=4 SU(2) cases. We show how the modular
anomaly equation obeyed by the deformed prepotential can be efficiently used to
derive its non-perturbative expression starting from the perturbative one. We
also show that the modular anomaly equation implies that S-duality is
implemented by means of an exact Fourier transform even for arbitrary values of
the deformation parameters, and then we argue that it is possible,
perturbatively in the deformation, to choose appropriate variables such that it
reduces to a Legendre transform.Comment: 30 pages, LeTeX2e. V2: references added, appendix B expanded, a few
typos correcte
Wrapped Magnetized Branes: Two Alternative Descriptions?
We discuss two inequivalent ways for describing magnetized D-branes wrapped N
times on a torus T^2. The first one is based on a non-abelian gauge bundle
U(N), while the second one is obtained by means of a Narain T-duality
transformation acting on a theory with non-magnetized branes. We construct in
both descriptions the boundary state and the open string vertices and show that
they give rise to different string amplitudes. In particular, the description
based on the gauge bundle has open string vertex operators with momentum
dependent Chan-Paton factors.Comment: 60 pages, LaTe
Superparticle and superstring in AdS_3 x S^3 Ramond-Ramond background in light-cone gauge
We discuss superparticle and superstring dynamics in AdS_3 x S^3 supported by
R-R 3-form background using light-cone gauge approach. Starting with the
superalgebra psu(1,1|2) + psu(1,1|2) representing the basic symmetry of this
background we find the light-cone superparticle Hamiltonian. We determine the
harmonic decomposition of light-cone superfield describing fluctuations of type
IIB supergravity fields expanded near AdS_3 x S^3 background and compute the
corresponding Kaluza-Klein spectrum. We fix the fermionic and bosonic
light-cone gauges in the covariant Green-Schwarz AdS_3 x S^3 superstring action
and find the light-cone string Hamiltonian. We also obtain a realization of the
generators of psu(1,1|2) + psu(1,1|2) in terms of the superstring 2-d fields in
the light-cone gauge.Comment: 32 pages, late
Superstring action in AdS_5 x S^5: kappa symmetry light cone gauge
As part of program to quantize superstrings in AdS_5 x S^5 background in
light cone approach we find the explicit form of the corresponding
Green-Schwarz action in fermionic light-cone kappa-symmetry gauge. The
resulting action is quadratic and quartic in fermions. In the flat space limit
it reduces to the standard light-cone Green-Schwarz action, and also has the
correct superparticle limit. We discuss fixing the bosonic light-cone gauge and
a reformulation of the action in terms of 2-d Dirac spinors.Comment: 32 pages, latex. v4: misprints corrected in Appendix A, to appear in
Phys Rev
Quantization of Superstrings in Ramond-Ramond Backgrounds
We present a perturbative study of Ramond-Ramond backgrounds in the NSR
formalism. We show how to perform sigma-model computations and discuss in
detail the structure of the BRST charge and picture-changing operators. Contact
terms play a vital role in the analysis. We also give evidence for a two loop
non-renormalization theorem for the background beta functions.Comment: 29 pages, 1 figure; uses LaTeX, epsf, hyperref packages; references
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