616 research outputs found
A Note on Embedding of M-Theory Corrections into Eleven-Dimensional Superspace
By analyzing eleven-dimensional superspace fourth-rank superfield strength
F-Bianchi identities, we show that M-theory corrections to eleven-dimensional
supergravity can not be embedded into the mass dimension zero constraints, such
as the (\g^{a b})_{\a\b} X_{a b}{}^c or i (\g^{a_1... a_5})_{\a\b} X_{a_1...
a_5}{}^c -terms in the supertorsion constraint T_{\a\b}{}^c. The only possible
modification of superspace constraint at dimension zero is found to be the
scaling of F_{\a\b c d} like F_{\a\b c d} = (1/2) \big(\g_{c d}\big)_{\a\b}
e^\Phi for some real scalar superfield \Phi, which alone is further shown not
enough to embed general M-theory corrections. This conclusion is based on the
dimension zero F-Bianchi identity under the two assumptions: (i) There are no
negative dimensional constraints on the F-superfield strength: F_{\a\b\g\d} =
F_{\a\b\g d} =0; (ii) The supertorsion T-Bianchi identities and F-Bianchi
identities are not modified by Chern-Simons terms. Our result can serve as a
powerful tool for future exploration of M-theory corrections embedded into
eleven-dimensional superspace supergravity.Comment: 14 pages, latex, some minor typos corrected, as well as old section 5
deleted, due to the subtlety about Chern-Simons term in F-Bianchi identitie
No N=4 Strings on Wolf Spaces
We generalize the standard supersymmetric Kazama-Suzuki coset
construction to the case by requiring the {\it non-linear}
(Goddard-Schwimmer) quasi-superconformal algebra to be realized on
cosets. The constraints that we find allow very simple geometrical
interpretation and have the Wolf spaces as their natural solutions. Our results
obtained by using components-level superconformal field theory methods are
fully consistent with standard results about supersymmetric
two-dimensional non-linear sigma-models and WZNW models on Wolf spaces.
We construct the actions for the latter and express the quaternionic structure,
appearing in the coset solution, in terms of the symplectic structure
associated with the underlying Freudenthal triple system. Next, we gauge the
QSCA and build a quantum BRST charge for the string propagating on
a Wolf space. Surprisingly, the BRST charge nilpotency conditions rule out the
non-trivial Wolf spaces as consistent string backgrounds.Comment: 31 pages, LaTeX, special macros are include
Parity Conservation in Supersymmetric Vector-Like Theories
We show that parity is conserved in vector-like supersymmetric theories, such
as supersymmetric QCD with massive quarks with no cubic couplings among chiral
multiplets, based on fermionic path-integrals, originally developed by Vafa and
Witten. We also look into the effect of supersymmetric breaking through gluino
masses, and see that the parity-conservation is intact also in this case. Our
conclusion is valid, when only bosonic parity-breaking observable terms are
considered in path-integrals like the original Vafa-Witten formulation.Comment: 14 pages, latex, no figures; replaced with corrections of exponent in
old eq.(2.8), misleading expressions in (3.19), comments on fermionic
parity-breaking terms, and some references adde
Simulator studies of the attack phase of an automatically controlled interceptor
The attack phase of the automatically controlled interceptor is studied in two parts. Part I is a limited simulation conducted to specify the lateral and longitudinal control systems for an automatic interceptor. The results are presented as Nyquist plots and time histories of the airplane variables. Part II uses the control systems developed in Part I, together with a dynamically perfect guidance system, to study the effect of the nonlinear terms in the complete equations of motion and nonlinear aerodynamics on the airplane response. The results are presented as time histories of the airplane and control surface motions
Renormalizability of N=1/2 Wess-Zumino model in superspace
In this letter we use the spurion field approach adopted in hep-th/0307099 in
order to show that by adding F and F^2 terms to the original lagrangian, the
N=1/2 Wess-Zumino model is renormalizable to all orders in perturbation theory.
We reformulate in superspace language the proof given in the recent work
hep-th/0307165 in terms of component fields.Comment: 8 pages, minor change
Families of N=2 Strings
In a given 4d spacetime bakcground, one can often construct not one but a
family of distinct N=2 string theories. This is due to the multiple ways N=2
superconformal algebra can be embedded in a given worldsheet theory. We
formulate the principle of obtaining different physical theories by gauging
different embeddings of the same symmetry algebra in the same ``pre-theory.''
We then apply it to N=2 strings and formulate the recipe for finding the
associated parameter spaces of gauging. Flat and curved target spaces of both
(4,0) and (2,2) signatures are considered. We broadly divide the gauging
choices into two classes, denoted by alpha and beta, and show them to be
related by T-duality. The distinction between them is formulated topologically
and hinges on some unique properties of 4d manifolds. We determine what their
parameter spaces of gauging are under certain simplicity ansatz for generic
flat spaces (R^4 and its toroidal compactifications) as well as some curved
spaces. We briefly discuss the spectra of D-branes for both alpha and beta
families.Comment: 66+1 pages, 2 tables, latex 2e, hyperref. ver2: typos corrected,
reference adde
Space-Time Supersymmetry of Extended Fermionic Strings in Dimensions
The fermionic string theory is revisited in light of its recently
proposed equivalence to the non-compact fermionic string model. The
issues of space-time Lorentz covariance and supersymmetry for the BRST
quantized strings living in uncompactified dimensions are
discussed. The equivalent local quantum supersymmetric field theory appears to
be the most transparent way to represent the space-time symmetries of the
extended fermionic strings and their interactions. Our considerations support
the Siegel's ideas about the presence of Lorentz symmetry as well as
at least one self-dual space-time supersymmetry in the theory of the
fermionic strings, though we do not have a compelling reason to argue about the
necessity of the {\it maximal} space-time supersymmetry. The world-sheet
arguments about the absence of all string massive modes in the physical
spectrum, and the vanishing of all string-loop amplitudes in the Polyakov
approach, are given on the basis of general consistency of the theory.Comment: 29 pages, LaTeX, ITP-UH-1/9
Anti-self-dual Maxwell solutions on hyperk\"ahler manifold and N=2 supersymmetric Ashtekar gravity
Anti-self-dual (ASD) Maxwell solutions on 4-dimensional hyperk\"ahler
manifolds are constructed. The N=2 supersymmetric half-flat equations are
derived in the context of the Ashtekar formulation of N=2 supergravity. These
equations show that the ASD Maxwell solutions have a direct connection with the
solutions of the reduced N=2 supersymmetric ASD Yang-Mills equations with a
special choice of gauge group. Two examples of the Maxwell solutions are
presented.Comment: 9 page
The N=4 string is the same as the N=2 string
We redo the quantization of the N=4 string, taking into account the
reducibility of the constraints. The result is equivalent to the N=2 string,
with critical dimension D=4 and signature (++--). The N=4 formulation has
several advantages: the sigma-model field equations are implied classically,
rather than by quantum/beta-function calculations; self-duality/chirality is
one of the super-Virasoro constraints; SO(2,2) covariance is manifest. This
reveals that the theory includes fermions, and is apparently spacetime
supersymmetric.Comment: 7 pg (uuencoded dvi file; otherwise same as original
Pure spinor superfields -- an overview
Maximally supersymmetric theories do not allow off-shell superspace
formulations with traditional superfields containing a finite set of auxiliary
fields. It has become clear that off-shell supersymmetric action formulations
of such models can be achieved by the introduction of pure spinors. In this
talk, an overview of this formalism is given, with emphasis on D=10
super-Yang-Mills theory and D=11 supergravity. This a somewhat expanded version
of a talk presented at the workshop "Breaking of supersymmetry and ultraviolet
divergences in extended supergravity" (BUDS), Laboratori Nazionali di Frascati,
March 25-28, 2013.Comment: 34 pp., 2 figs., contributions to the proceedings of the workshop
"Breaking of supersymmetry and ultraviolet divergences in extended
supergravity" (BUDS), Laboratori Nazionali di Frascati, March 25-28, 201
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