5,360 research outputs found
Minimal D=4 supergravity from the superMaxwell algebra
We show that the first-order D=4, N=1 pure supergravity lagrangian four-form
can be obtained geometrically as a quadratic expression in the curvatures of
the Maxwell superalgebra. This is achieved by noticing that the relative
coefficient between the two terms of the Lagrangian that makes the action
locally supersymmetric also determines trivial field equations for the gauge
fields associated with the extra generators of the Maxwell superalgebra. Along
the way, a convenient geometric procedure to check the local supersymmetry of a
class of lagrangians is developed.Comment: Plain latex, 14 pages. Two misprints corrected, one reference adde
Superalgebra cohomology, the geometry of extended superspaces and superbranes
We present here a cohomological analysis of the new spacetime superalgebras
that arise in the context of superbrane theory. They lead to enlarged
superspaces that allow us to write D-brane actions in terms of fields
associated with the additional superspace variables. This suggests that there
is an extended superspace/worldvolume fields democracy for superbranes.Comment: 12 pages, LATEX. Invited lecture delivered at the XXXVII Karpacz
Winter School on "New Developments in Fundamental Interaction Theories" (6-15
February, 2001, Karpacz, Poland). To be published in the Proceeding
One-dimensional solitary waves in singular deformations of SO(2) invariant two-component scalar field theory models
In this paper we study the structure of the manifold of solitary waves in
some deformations of SO(2) symmetric two-component scalar field theoretical
models in two-dimensional Minkowski space. The deformation is chosen in order
to make the analogous mechanical system Hamilton-Jacobi separable in polar
coordinates and displays a singularity at the origin of the internal plane. The
existence of the singularity confers interesting and intriguing properties to
the solitary waves or kink solutions.Comment: 25 pages, 18 figure
Contractions from to the M-theory superalgebra extended by additional fermionic generators
We study here the generalized Weimar-Woods contractions of the superalgebra
in order to obtain a suitable algebra that could
describe the gauge group of supergravity. The contracted superalgebras
are assumed to be given in terms of fermionic extensions of the M-theory
superalgebra. We show that the only superalgebra of this type obtained by
contraction is the only one for which the three-form of supergravity
cannot be trivialized. Therefore, supergravity cannot be connected in
this way with a contraction of
Bosonic D=11 supergravity from a generalized Chern-Simons action
It is shown that the action of the bosonic sector of D=11 supergravity may be
obtained by means of a suitable scaling of the originally dimensionless fields
of a generalized Chern-Simons action. This follows from the eleven-form
CS-potential of the most general linear combination of closed, gauge invariant
twelve-forms involving the sp(32)-valued two-form curvatures supplemented by a
three-form field. In this construction, the role of the skewsymmetric
four-index auxiliary function needed for the first order formulation of
supergravity is played by the gauge field associated with the five Lorentz
indices generator of the bosonic sp(32) subalgebra of osp(1|32).Comment: Misprints corrected, to appear in NPB plain latex, no figures, 25
page
Generalizations of Maxwell (super)algebras by the expansion method
The Lie algebras expansion method is used to show that the Maxwell
(super)algebras and some of their generalizations can be derived in a simple
way as particular expansions of o(3,2) and osp(N|4).Comment: Discussion slightly expanded; published versio
On the semiclassical mass of -kinks
One-loop mass shifts to the classical masses of stable kinks arising in a
massive non-linear -sigma model are computed. Ultraviolet
divergences are controlled using the heat kernel/zeta function regularization
method. A comparison between the results achieved from exact and
high-temperature asymptotic heat traces is analyzed in depth.Comment: RevTex file, 15 pages, 2 figures. Version to appear in Journal of
Physics
Two-twistor particle models and free massive higher spin fields
We present D=3 and D=4 models for massive particles moving in a new type of
enlarged spacetime, with D-1 additional vector coordinates, which after
quantization lead to the towers of massive higher spin (HS) free fields. Two
classically equivalent formulations are presented: one with a hybrid
spacetime/bispinor geometry and a second described by a free two-twistor
dynamics with constraints. After quantization in the D=3 and D=4 cases, the
wave functions are given as functions on the SL(2,R) and SL(2,C) group
manifolds respectively, and describe arbitrary on-shell momenta and spin
degrees of freedom. Finally, the D=6 case and possible supersymmetric
extensions are mentioned.Comment: 37 pages, plain latex, v2. Text in Secs. 1 nd 4 enlarged, references
added. Version to appear in JHE
The Kink variety in systems of two coupled scalar fields in two space-time dimensions
In this paper we describe the moduli space of kinks in a class of systems of
two coupled real scalar fields in (1+1) Minkowskian space-time. The main
feature of the class is the spontaneous breaking of a discrete symmetry of
(real) Ginzburg-Landau type that guarantees the existence of kink topological
defects.Comment: 12 pages, 5 figures. To appear in Phys. Rev.
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