871 research outputs found
Current Density Distributions and a Supersymmetric Action for Interacting Brane Systems
We propose a method to obtain a manifestly supersymmetric action functional
for interacting brane systems. It is based on the induced map of the
worldvolume of low-dimensional branes into the worldvolume of the space-time
filling brane ((D-1)-brane), which may be either dynamical or auxiliary, and
implies an identification of Grassmann coordinate fields of lower dimensional
branes with an image of the Grassmann coordinate fields of that (D-1)-brane.
With this identification the covariant current distribution forms with support
on the superbrane worldvolumes become invariant under the target space
supersymmetry and can be used to write the coupled superbrane action as an
integral over the D-dimensional manifolds ((D-1)-brane worldvolume). We compare
the equations derived from this new ('Goldstone fermion embedded') action with
the ones produced by a more straightforward generalization of the free brane
actions based on the incorporation of the boundary terms with Lagrange
multipliers ('superspace embedded' action). We find that both procedures
produce the same equations of motion and thus justify each other. Both actions
are presented explicitly for the coupled system of a D=10 super-D3-brane and a
fundamental superstring which ends on the super-D3-brane.Comment: 14 pages, latex, no figure
BPS preons in M-theory and supergravity
After introducing the notion of BPS preons as the basic constituents of
M-theory, we discuss the recent negative results in the search for solutions of
the D=10 and D=11 supergravity equations preserving 31/32 supersymmetries i.e.,
of preonic solutions. The absence of these supergravity preonic solutions may
point out to a pure quantum nature of BPS preons, manifesting itself in the
need of incorporating quantum (stringy/M-theoretic) corrections to the
supergravity equations.Comment: plain latex, 10 pages. Talk delivered at the Workshop of the RTN
network "Constituents, fundamental forces and Symmetries of the Universe",
Napoli October 9-13, 200
Multiple M0-brane equations in eleven dimensional pp-wave superspace and BMN matrix model
We obtain the Matrix model equations in the background of the maximally
supersymmetric pp-wave solution of the 11D supergravity and discuss its
relation with the Berenstein-Maldacena-Nastase (BMN) model.Comment: 14 pages, revtex4, no figure
A Polynomial First Order Action for the Dirichlet 3-brane
A new first order action for type IIB Dirichlet 3-brane is proposed. Its form
is inspired by the superfield equations of motion obtained recently from the
generalized action principle. The action involves auxiliary symmetric spin
tensor fields. It seems promising for a reformulation of the generalized action
in a structure most adequate for investigating the extrinsic geometry of the
super-3- brane, but also for further studies of string dualities.Comment: Eq. (53) corrected, acknowledgement added, 13 pages, LATEX, no
figure
Twistor string as tensionless superstring
We give a brief review of the twistor string approach to supersymmetric
Yang-Mills theories with an emphasis on the different formulations of
(super)string models in supertwistor space and their superspace form. We
discuss the classical equivalence among the Siegel closed twistor string and
the Lorentz harmonics formulation of the (N=4) tensionless superstring, and
notice the possible relation of the twistor string to the D=10 Green-Schwarz
superstring action, as well as to models in the enlarged, tensorial superspaces
that are relevant in higher spin theories.Comment: plain latex, 9 pages. Talk delivered at the Workshop of the RTN
network 'Constituents, fundamental forces and Symmetries of the Universe',
Napoli October 9-13, 2006, to appear in Fortschritte der Physi
Superstring 'ending' on super-D9-brane: a supersymmetric action functional for the coupled brane system
A supersymmetric action functional describing the interaction of the
fundamental superstring with the D=10, type IIB Dirichlet super-9-brane is
presented. A set of supersymmetric equations for the coupled system is obtained
from the action principle. It is found that the interaction of the string
endpoints with the super-D9-brane gauge field requires some restrictions for
the image of the gauge field strength. When those restrictions are not imposed,
the equations imply the absence of the endpoints, and the equations coincide
either with the ones of the free super-D9-brane or with the ones for the free
closed type IIB superstring. Different phases of the coupled system are
described. A generalization to an arbitrary system of intersecting branes is
discussed.Comment: 44 pages, latex, no figure
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
Superembedding Approach and S-Duality. A unified description of superstring and super-D1-brane
It is proved that a basic superembedding equation for the 2-dimensional
worldsheet superspace embedded into D=10 type IIB superspace
provides a universal, S-duality invariant description of a
fundamental superstring and super-D1-brane. We work out generalized action
principle, obtain superfield equations of motion for both these objects and
find how the S-duality transformations relate the superfield equations of
superstring and super-D1-brane.
The superembedding of 6-dimensional worldsheet superspace into
the D=10 type IIB superspace will probably provide a similar universal
description for the set of type IIB super-NS5-brane, super-D5-brane and a
Kaluza-Klein monopole (super-KK5-brane).Comment: 30 pages, LATEX, no figures. V2: misprints and typos corrected,
references added. V3: misprints corrected, version to appear in Nucl.Phys.
Towards the M(atrix) model action in an arbitrary 11D supergravity background. Progress report
We are searching for the action principle for multiple M0-brane (multiple
M-wave or mM0) system starting from the mM0 equations of motion obtained in the
frame of superembedding approach. Surprisingly, the way from these equations to
the action happens to be hampered by a problem which suggests a possible
generalization of the action principle which we call "hierarchical action
principle".Comment: 4 pages, iopams style, contribution to the ERE 2010 Proceedings, to
be published in J.phys. Conf. Se
Superembedding approach to M0-brane and multiple M0-brane system
We study the possibility to describe multiple M0-brane system in the frame of
superembedding approach. The simplest framework is provided by the maximally
supersymmetric non-Abelian SU(N) Yang-Mills supermultiplet on the d=1 N=16
superspace the embedding of which to the target D=11 supergravity superspace is
determined by the so-called superembedding equation, characteristic of the
worldline superspace of a single M0-brane. We use it to obtain a covariant
generalization of the Matrix model equations describing the multiple M0-system
in flat target superspace.Comment: 14 pages, LaTeX, no figures. V2. Misprints corrected, to appear in
Phys. Lett. B
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