4,286 research outputs found
On the supergravity formulation of mirror symmetry in generalized Calabi-Yau manifolds
We derive the complete supergravity description of the N=2 scalar potential
which realizes a generic flux-compactification on a Calabi-Yau manifold
(generalized geometry). The effective potential V_{eff}=V_{(\partial_Z V=0)},
obtained by integrating out the massive axionic fields of the special
quaternionic manifold, is manifestly mirror symmetric, i.e. invariant with
respect to {\rm Sp}(2 h_2+2)\times {\rm Sp}(2 h_1+2) and their exchange, being
h_1, h_2 the complex dimensions of the underlying special geometries. {\Scr
V}_{eff} has a manifestly N=1 form in terms of a mirror symmetric
superpotential W$ proposed, some time ago, by Berglund and Mayr.Comment: 14 pages, LaTeX sourc
Five-Brane Effective Field Theory on Calabi-Yau Threefolds
We consider the compactification of the dual form of
supergravity on a six-dimensional Calabi-Yau manifold. An off-shell
supergravity effective Lagrangian in four dimensions can be constructed in a
dual version of the gravitational sector (new-minimal supergravity form).
Superspace duality has a simple interpretation in terms of Poincar\'{e} duality
of two-form cohomology. The resulting Lagrangian may describe the
low-energy point-field limit of a five-brane theory, dual to string theory,
provided Calabi-Yau spaces are consistent vacua of such dual theory.Comment: 16 pages, LaTeX, CERN-Th.6914/93 POLFIS-TH.04/93 UCLA/93/TEP/1
Orientifolds, Brane Coordinates and Special Geometry
We report on the gauged supergravity analysis of Type IIB vacua on K3x T2/Z2
orientifold in the presence of D3-D7-branes and fluxes. We discuss
supersymmetric critical points correspond to Minkowski vacua and the related
fixing of moduli, finding agreement with previous analysis. An important role
is played by the choice of the symplectic holomorphic sections of special
geometry which enter the computation of the scalar potential. The related
period matrix N is explicitly given. The relation between the special geometry
and the Born--Infeld action for the brane moduli is elucidated.Comment: 24 pages, contribution to the proceedings of "DeserFest", Ann Arbor,
Michigan, 3-6 April 200
Spontaneously broken supergravity: Old and new facts
We report on some recent investigations of the structure of the four
dimensional gauged supergravity Lagrangian which emerges from flux and
Scherk-Schwarz compactifications in higher dimensions. Special attention is
given to the gauge structure of M-theory compactified on a seven torus with
4-form and geometrical (spin connection) fluxes turned on. A class of vacua,
with flat space-time and described by ``no-scale'' supergravity models, is
analyzed.Comment: 14 pages, LaTeX file, imprecise statement correcte
On the Embedding of Space-Time Symmetries into Simple Superalgebras
We explore the embedding of Spin groups of arbitrary dimension and signature
into simple superalgebras in the case of extended supersymmetry. The
R-symmetry, which generically is not compact, can be chosen compact for all the
cases that are congruent mod 8 to the physical conformal algebra so(,2),
. An grading of the superalgebra is found in all cases.
Central extensions of super translation algebras are studied in this framework.Comment: AMS LaTeX, 16 page
Curvatures and potential of M-theory in D=4 with fluxes and twist
We give the curvatures of the free differential algebra (FDA) of M--theory
compactified to D=4 on a twisted seven--torus with the 4--form flux switched
on. Two formulations are given, depending on whether the 1--form field
strengths of the scalar fields (originating from the 3--form gauge field
) are included or not in the FDA. We also give the bosonic
equations of motion and discuss at length the scalar potential which emerges in
this type of compactifications. For flat groups we show the equivalence of this
potential with a dual formulation of the theory which has the full \rE_{7(7)}
symmetry.Comment: 14 pages, LaTeX source, typos correcte
Scalar potential for the gauged Heisenberg algebra and a non-polynomial antisymmetric tensor theory
We study some issues related to the effective theory of Calabi-Yau
compactifications with fluxes in Type II theories. At first the scalar
potential for a generic electric abelian gauging of the Heisenberg algebra,
underlying all possible gaugings of RR isometries, is presented and shown to
exhibit, in some circumstances, a "dual'' no-scale structure under the
interchange of hypermultiplets and vector multiplets. Subsequently a new
setting of such theories, when all RR scalars are dualized into antisymmetric
tensors, is discussed. This formulation falls in the class of non-polynomial
tensor theories considered long ago by Freedman and Townsend and it may be
relevant for the introduction of both electric and magnetic charges.Comment: 11 pages LaTe
N=1 reductions of N=2 supergravity in the presence of tensor multiplets
We consider consistent truncations of N=2 supergravites in the presence of
tensor multiplets (dual to hypermultiplets) as they occur in type IIB
compactifications on Calabi--Yau orientifolds. We analyze in detail the scalar
potentials encompassing these reductions when fluxes are turned on and study
vacua of the N=1 phases.Comment: 40 pages, LaTeX, typos corrected, references adde
c--Map,very Special Quaternionic Geometry and Dual Ka\"hler Spaces
We show that for all very special quaternionic manifolds a different N=1
reduction exists, defining a Kaehler Geometry which is ``dual'' to the original
very special Kaehler geometry with metric G_{a\bar{b}}= - \partial_a \partial_b
\ln V (V={1/6}d_{abc}\lambda^a \lambda^b \lambda^c). The dual metric
g^{ab}=V^{-2} (G^{-1})^{ab} is Kaehler and it also defines a flat potential as
the original metric. Such geometries and some of their extensions find
applications in Type IIB compactifications on Calabi--Yau orientifolds.Comment: 9 pages, LaTeX, typos corrected, comments adde
Twisted tori and fluxes: a no go theorem for Lie groups of weak G_2 holonomy
In this paper we prove the theorem that there exists no 7--dimensional Lie
group manifold G of weak G2 holonomy.
We actually prove a stronger statement, namely that there exists no
7--dimensional Lie group with negative definite Ricci tensor Ric_{IJ}.
This result rules out (supersymmetric and non--supersymmetric)
Freund--Rubin solutions of M--theory of the form AdS_4\times G and
compactifications with non--trivial 4--form fluxes of Englert type on an
internal group manifold G. A particular class of such backgrounds which, by our
arguments are excluded as bulk supergravity compactifications corresponds to
the so called compactifications on twisted--tori, for which G has structure
constants with vanishing trace . On the other
hand our result does not have bearing on warped compactifications of M--theory
to four dimensions and/or to compactifications in the presence of localized
sources (D--branes, orientifold planes and so forth). Henceforth our result
singles out the latter compactifications as the preferred hunting grounds that
need to be more systematically explored in relation with all compactification
features involving twisted tori.Comment: 38 pages, tar file containing LaTeX source and youngtab.st
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