9,974 research outputs found
On The spectrum of a Noncommutative Formulation of the D=11 Supermembrane with Winding
A regularized model of the double compactified D=11 supermembrane with
nontrivial winding in terms of SU(N) valued maps is obtained. The condition of
nontrivial winding is described in terms of a nontrivial line bundle introduced
in the formulation of the compactified supermembrane. The multivalued
geometrical objects of the model related to the nontrivial wrapping are
described in terms of a SU(N) geometrical object which in the
limit, converges to the symplectic connection related to the area preserving
diffeomorphisms of the recently obtained non-commutative description of the
compactified D=11 supermembrane.(I. Martin, J.Ovalle, A. Restuccia. 2000,2001)
The SU(N) regularized canonical lagrangian is explicitly obtained. In the limit it converges to the lagrangian in (I.Martin, J.Ovalle,
A.Restuccia. 2000,2001) subject to the nontrivial winding condition. The
spectrum of the hamiltonian of the double compactified D=11 supermembrane is
discussed.
Generically, it contains local string like spikes with zero energy.
However the sector of the theory corresponding to a principle bundle
characterized by the winding number , described by the SU(N) model we
propose, is shown to have no local string-like spikes and hence the spectrum of
this sector should be discrete.Comment: 16 pages.Latex2
Consistent truncation of d = 11 supergravity on AdS_4 x S^7
We study the system of equations derived twenty five years ago by B. de Wit
and the first author [Nucl. Phys. B281 (1987) 211] as conditions for the
consistent truncation of eleven-dimensional supergravity on AdS_4 x S^7 to
gauged N = 8 supergravity in four dimensions. By exploiting the E_7(7)
symmetry, we determine the most general solution to this system at each point
on the coset space E_7(7)/SU(8). We show that invariants of the general
solution are given by the fluxes in eleven-dimensional supergravity. This
allows us to both clarify the explicit non-linear ansatze for the fluxes given
previously and to fill a gap in the original proof of the consistent
truncation. These results are illustrated with several examples.Comment: 41 pages, typos corrected, published versio
Viscous fingering in periodically heterogeneous porous media. II. Numerical simulations
N=2 Conformal Superspace in Four Dimensions
We develop the geometry of four dimensional N=2 superspace where the entire
conformal algebra of SU(2,2|2) is realized linearly in the structure group
rather than just the SL(2,C) x U(2)_R subgroup of Lorentz and R-symmetries,
extending to N=2 our prior result for N=1 superspace. This formulation
explicitly lifts to superspace the existing methods of the N=2 superconformal
tensor calculus; at the same time the geometry, when degauged to SL(2,C) x
U(2)_R, reproduces the existing formulation of N=2 conformal supergravity
constructed by Howe.Comment: 43 pages; v2 references added, acknowledgments update
New supersymmetric higher-derivative couplings: Full N=2 superspace does not count!
An extended class of N=2 locally supersymmetric invariants with
higher-derivative couplings based on full superspace integrals, is constructed.
These invariants may depend on unrestricted chiral supermultiplets, on vector
supermultiplets and on the Weyl supermultiplet. Supersymmetry is realized
off-shell. A non-renormalization theorem is proven according to which none of
these invariants can contribute to the entropy and electric charges of BPS
black holes. Some of these invariants may be relevant for topological string
deformations.Comment: 24 pages, v2: version published in JHEP, one reference added and
typos corrected, v3: reference adde
On BPS bounds in D=4 N=2 gauged supergravity II: general matter couplings and black hole masses
We continue the analysis of BPS bounds started in arXiv:1110.2688, extending
it to the full class of N=2 gauged supergravity theories with arbitrary vector
and hypermultiplets. We derive the general form of the asymptotic charges for
asymptotically flat (M_4), anti-de Sitter (AdS_4), and magnetic anti-de Sitter
(mAdS_4) spacetimes. Some particular examples from black hole physics are given
to explicitly demonstrate how AdS and mAdS masses differ when solutions with
non-trivial scalar profiles are considered.Comment: 21 pages; v2 added reference, published version; v3 minor correction
Stable de Sitter Vacua in 4 Dimensional Supergravity Originating from 5 Dimensions
The five dimensional stable de Sitter ground states in N=2 supergravity
obtained by gauging SO(1,1) symmetry of the real symmetric scalar manifold (in
particular a generic Jordan family manifold of the vector multiplets)
simultaneously with a subgroup R_s of the R-symmetry group descend to four
dimensional de Sitter ground states under certain conditions. First, the
holomorphic section in four dimensions has to be chosen carefully by using the
symplectic freedom in four dimensions; and second, a group contraction is
necessary to bring the potential into a desired form. Under these conditions,
stable de Sitter vacua can be obtained in dimensionally reduced theories (from
5D to 4D) if the semi-direct product of SO(1,1) with R^(1,1) together with a
simultaneous R_s is gauged. We review the stable de Sitter vacua in four
dimensions found in earlier literature for N=2 Yang-Mills Einstein supergravity
with SO(2,1) x R_s gauge group in a symplectic basis that comes naturally after
dimensional reduction. Although this particular gauge group does not descend
directly from five dimensions, we show that, its contraction does. Hence, two
different theories overlap in certain limits. Examples of stable de Sitter
vacua are given for the cases: (i) R_s=U(1)_R, (ii) R_s=SU(2)_R, (iii) N=2
Yang-Mills/Einstein Supergravity theory coupled to a universal hypermultiplet.
We conclude with a discussion regarding the extension of our results to
supergravity theories with more general homogeneous scalar manifolds.Comment: 54 page
On the classification of buoyancy-driven chemo-hydrodynamic instabilities of chemical fronts
Electric and magnetic charges in N=2 conformal supergravity theories
General Lagrangians are constructed for N=2 conformal supergravity theories
in four space-time dimensions involving gauge groups with abelian and/or
non-abelian electric and magnetic charges. The charges are encoded in the gauge
group embedding tensor. The scalar potential induced by the gauge interactions
is quadratic in this tensor, and, when the embedding tensor is treated as a
spurionic quantity, it is formally covariant with respect to electric/magnetic
duality. This work establishes a general framework for studying any deformation
induced by gauge interactions of matter-coupled N=2 supergravity theories. As
an application, full and residual supersymmetry realizations in maximally
symmetric space-times are reviewed. Furthermore, a general classification is
presented of supersymmetric solutions in
space-times. As it turns out, these solutions allow either eight or four
supersymmetries. With four supersymmetries, the spinorial parameters are
Killing spinors of that are constant on , so that they
carry no spin, while the bosonic background is rotationally invariant.Comment: 49 pages, typos correcte
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