17 research outputs found
On the Opening of Branes
We relate, in 10 and 11 dimensional supergravities, configurations of
intersecting closed branes with vanishing binding energy to configurations
where one of the branes opens and has its boundaries attached to the other.
These boundaries are charged with respect to fields living on the closed brane.
The latter hosts electric and magnetic charges stemming from dual pairs of open
branes terminating on it. We show that charge conservation, gauge invariance
and supersymmetry entirely determine these charges and these fields, which can
be seen as Goldstone fields of broken supersymmetry. Open brane boundary
charges can annihilate, restoring the zero binding energy configuration. This
suggests emission of closed branes by branes, a generalization of closed string
emission by D-branes. We comment on the relation of the Goldstone fields to
matrix models approaches to M-theory.Comment: 13 pages, LaTeX, no figure
An M-theory solution from null roots in E11
We find a purely gravitational classical solution of
M-theory/eleven-dimensional supergravity which corresponds to a solution of the
E10 brane sigma-model involving a null root. This solution is not
supersymmetric and is regularly embedded into E11.Comment: 10 page
G+++ Invariant Formulation of Gravity and M-Theories: Exact BPS Solutions
We present a tentative formulation of theories of gravity with suitable
matter content, including in particular pure gravity in D dimensions, the
bosonic effective actions of M-theory and of the bosonic string, in terms of
actions invariant under very-extended Kac-Moody algebras G+++. We conjecture
that they host additional degrees of freedom not contained in the conventional
theories. The actions are constructed in a recursive way from a level expansion
for all very-extended algebras G+++. They constitute non-linear realisations on
cosets, a priori unrelated to space-time, obtained from a modified Chevalley
involution. Exact solutions are found for all G+++. They describe the algebraic
properties of BPS extremal branes, Kaluza-Klein waves and Kaluza-Klein
monopoles. They illustrate the generalisation to all G+++ invariant theories of
the well-known duality properties of string theories by expressing duality as
Weyl invariance in G+++. Space-time is expected to be generated dynamically. In
the level decomposition of E8+++ = E11, one may indeed select an A10
representation of generators Pa which appears to engender space-time
translations by inducing infinite towers of fields interpretable as field
derivatives in space and time.Comment: Latex 45 pages, 1 figure. Discussion on pages 19 and 20 altered.
Appendix B amplified. 4 footnotes added. 2 references added. Acknowledgments
updated. Additional minor correction
Hidden Symmetries and Dirac Fermions
In this paper, two things are done. First, we analyze the compatibility of
Dirac fermions with the hidden duality symmetries which appear in the toroidal
compactification of gravitational theories down to three spacetime dimensions.
We show that the Pauli couplings to the p-forms can be adjusted, for all simple
(split) groups, so that the fermions transform in a representation of the
maximal compact subgroup of the duality group G in three dimensions. Second, we
investigate how the Dirac fermions fit in the conjectured hidden overextended
symmetry G++. We show compatibility with this symmetry up to the same level as
in the pure bosonic case. We also investigate the BKL behaviour of the
Einstein-Dirac-p-form systems and provide a group theoretical interpretation of
the Belinskii-Khalatnikov result that the Dirac field removes chaos.Comment: 30 page
Counting supersymmetric branes
Maximal supergravity solutions are revisited and classified, with particular
emphasis on objects of co-dimension at most two. This class of solutions
includes branes whose tension scales with g_s^{-\sigma} for \sigma>2. We
present a group theory derivation of the counting of these objects based on the
corresponding tensor hierarchies derived from E11 and discrete T- and U-duality
transformations. This provides a rationale for the wrapping rules that were
recently discussed for \sigma<4 in the literature and extends them. Explicit
supergravity solutions that give rise to co-dimension two branes are
constructed and analysed.Comment: 1+33 pages. To the memory of Laurent Houart. v2: Published version
with added reference
Finite and infinite-dimensional symmetries of pure N=2 supergravity in D=4
We study the symmetries of pure N=2 supergravity in D=4. As is known, this
theory reduced on one Killing vector is characterised by a non-linearly
realised symmetry SU(2,1) which is a non-split real form of SL(3,C). We
consider the BPS brane solutions of the theory preserving half of the
supersymmetry and the action of SU(2,1) on them. Furthermore we provide
evidence that the theory exhibits an underlying algebraic structure described
by the Lorentzian Kac-Moody group SU(2,1)^{+++}. This evidence arises both from
the correspondence between the bosonic space-time fields of N=2 supergravity in
D=4 and a one-parameter sigma-model based on the hyperbolic group SU(2,1)^{++},
as well as from the fact that the structure of BPS brane solutions is neatly
encoded in SU(2,1)^{+++}. As a nice by-product of our analysis, we obtain a
regular embedding of the Kac-Moody algebra su(2,1)^{+++} in e_{11} based on
brane physics.Comment: 70 pages, final version published in JHE
Intersection Rules for p-Branes
We present a general rule determining how extremal branes can interesect in a
configuration with zero binding energy. The rule is derived in a model
independent way and in arbitrary spacetime dimensions by solving the
equations of motion of gravity coupled to a dilaton and several different
-form field strengths. The intersection rules are all compatible with
supersymmetry, although derived without using it. We then specialize to the
branes occurring in type II string theories and in M-theory. We show that the
intersection rules are consistent with the picture that open branes can have
boundaries on some other branes. In particular, all the D-branes of dimension
, with , can have boundaries on the solitonic 5-brane.Comment: 15 pages, LaTeX, no figures. One reference modified; to appear in
Phys. Lett.
Bound States of String Theory and Beyond
All bound states of fundamental strings, D-branes and NS-branes of string
theory, both type-IIA and type-IIB, which may be described by a null geodesic
motion on the coset G/K(G) where G is a group of type A, D or E embedded within
E(11) are presented.Comment: 54+1 pages, 6 figures, 3 data files; typos corrected, added extended
discussion of the temporal involutio
Brane fusion in the bosonic string and the emergence of fermionic strings
We review the emergence of the ten-dimensional fermionic closed string theories from subspaces of the Hilbert space of the 26-dimensional bosonic closed string theory compactified on an E8 Ă— SO(16) lattice. They arise from a consistent truncation procedure which generates space-time fermions out of bosons. This procedure is extended to open string sectors. We prove that truncation of the unique tadpole-free SO(213) bosonic string theory compactified on the above lattice determines the anomaly free Chan-Paton group of the type-I theory and the consistent Chan-Paton groups of type-O theories. It also predicts the tension of space-filling D-branes in these fermionic theories. The derivation of these fermionic string properties from bosonic considerations alone points towards a dynamical origin of the truncation process. Space-time fermions and supersymmetries would then arise from bosonic degrees of freedom and no fermionic degrees of freedom would be needed in a fundamental theory of quantum gravity