21 research outputs found
A Twistor Formulation of the Non-Heterotic Superstring with Manifest Worldsheet Supersymmetry
We propose a new formulation of the type II superstring which is
manifestly invariant under both target-space supersymmetry and worldsheet
super reparametrizations. This gives rise to a set of twistor
(commuting spinor) variables, which provide a solution to the two Virasoro
constraints. The worldsheet supergravity fields are shown to play the r\^ole of
auxiliary fields.Comment: 21p., LaTe
Tensionless String in the Notoph Background
We study the interaction between a tensionless (null) string and an
antisymmetric background field B_{ab} using a 2-component spinor formalism. A
geometric condition for the absence of such an interaction is formulated. We
show that only one gauge-invariant degree of freedom of the field B_{ab} does
not satisfy this condition. Identification of this degree of freedom with the
notoph field \phi of Ogievetskii-Polubarinov-Kalb-Ramond is suggested.
Application of a two-component spinor formalism allows us a reduction of the
complete system of non-linear partial differential equations and constraints
governing the interacting null string dynamics to a system of linear
differential equations for the basis spinors of the spin-frame. We find that
total effect of the interaction is contained in a single derivation coefficient
which is identified with the notoph field.Comment: 15 pages, no figures, RevTeX 3.
New Superembeddings for Type II Superstrings
Possible ways of generalization of the superembedding approach for the
supersurfaces with the number of Grassmann directions being less than the half
of that for the target superspace are considered on example of Type II
superstrings. Focus is on n=(1,1) superworldsheet embedded into D=10 Type II
superspace that is of the interest for establishing a relation with the NSR
string.Comment: 26 pages, LaTeX, JHEP.cls and JHEP.bst style files are used; v2:
misprints corrected, comments, acknowledgments, references adde
Generalized action principle and extrinsic geometry for N=1 superparticle
It is proposed the generalized action functional for N=1 superparticle in
D=3,4,6 and 10 space-time dimensions. The superfield geometric approach
equations describing superparticle motion in terms of extrinsic geometry of the
worldline superspace are obtained on the base of the generalized action. The
off-shell superdiffeomorphism invariance (in the rheonomic sense) of the
superparticle generalized action is proved. It was demonstrated that the half
of the fermionic and one bosonic (super)fields disappear from the generalized
action in the analytical basis. Superparticle interaction with Abelian gauge
theory is considered in the framework of this formulation. The geometric
approach equations describing superparticle motion in Abelian background are
obtained.Comment: 31 pages. Late
SUPERSTRINGS AND SUPERMEMBRANES IN THE DOUBLY SUPERSYMMETRIC GEOMETRICAL APPROACH
We perform a generalization of the geometrical approach to describing
extended objects for studying the doubly supersymmetric twistor--like
formulation of super--p--branes. Some basic features of embedding world
supersurface into target superspace specified by a geometrodynamical condition
are considered. It is shown that the main attributes of the geometrical
approach, such as the second fundamental form and extrinsic torsion of the
embedded surface, and the Codazzi, Gauss and Ricci equations, have their doubly
supersymmetric counterparts. At the same time the embedding of supersurface
into target superspace has its particular features. For instance, the embedding
may cause more rigid restrictions on the geometrical properties of the
supersurface. This is demonstrated with the examples of an N=1 twistor--like
supermembrane in D=11 and type II superstrings in D=10, where the
geometrodynamical condition causes the embedded supersurface to be minimal and
puts the theories on the mass shell.Comment: 45 pages, LaTeX, 3 appendicie
Three approaches to data analysis
In this book, the following three approaches to data analysis are presented: - Test Theory, founded by Sergei V. Yablonskii (1924-1998); the first publications appeared in 1955 and 1958, - Rough Sets, founded by Zdzisław I. Pawlak (1926-2006); the first publications appeared in 1981 and 1982, - Logical Analysis of Data, founded by Peter L. Hammer (1936-2006); the first publications appeared in 1986 and 1988. These three approaches have much in common, but researchers active in one of these areas often have a limited knowledge about the results and methods developed in the other two. On the other hand, each of the approaches shows some originality and we believe that the exchange of knowledge can stimulate further development of each of them. This can lead to new theoretical results and real-life applications and, in particular, new results based on combination of these three data analysis approaches can be expected