2,921 research outputs found
Conformal internal symmetry of -models coupled to gravity and a dilaton
General Relativity reduced to two dimensions possesses a large group of
symmetries that exchange classical solutions. The associated Lie algebra is
known to contain the affine Kac-Moody algebra and half of a real
Witt algebra. In this paper we exhibit the full symmetry under the semi-direct
product of \Lie{A_1^{(1)}} by the Witt algebra \Lie{\Wir}. Furthermore we
exhibit the corresponding hidden gauge symmetries. We show that the theory can
be understood in terms of an infinite dimensional potential space involving all
degrees of freedom: the dilaton as well as matter and gravitation. In the
dilaton sector the linear system that extends the previously known Lax pair has
the form of a twisted self-duality constraint that is the analog of the
self-duality constraint arising in extended supergravities in higher spacetime
dimensions. Our results furnish a group theoretical explanation for the
simultaneous occurrence of two spectral parameters, a constant one () and a
variable one (). They hold for all non-linear -models that are
obtained by dimensional reduction of models in three dimensions coupled
to pure gravity. In that case the Lie algebra is \Lie{\Wir \semi G^{(1)}};
this symmetry acts on a set of off shell fields (in a fixed gauge) and
preserves the equations of motion.Comment: 44 pages, LATE
Gauged Supergravities in Three Dimensions: A Panoramic Overview
Maximal and non-maximal supergravities in three spacetime dimensions allow
for a large variety of semisimple and non-semisimple gauge groups, as well as
complex gauge groups that have no analog in higher dimensions. In this
contribution we review the recent progress in constructing these theories and
discuss some of their possible applications.Comment: 32 pages, 1 figure, Proceedings of the 27th Johns Hopkins workshop:
Goteborg, August 2003; references adde
Insect pathogenic fungi in biological control: status and future challenges
In Europe, insect pathogenic fungi have in decades played a significant role in biological control of insects. With respect to the different strategies of biological control and with respects to the different genera of insect pathogenic fungi, the success and potential vary, however. Classical biological control: no strong indication of potential. Inundation and inoculation biological control: success stories with the genera Metarhizium, Beauveria, Isaria/Paecilomyces and Lecanicillium (previously Verticillium). However, the genotypes employed seem to include a narrow spectrum of the many potentially useful genotypes. Conservation biological control: Pandora and Entomophthora have a strong potential, but also Beauveria has a potential to be explored further. The main bottleneck for further exploitation of insect pathogenic fungi in biological control is the limited knowledge of host pathogen interaction at the fungal genotype level
Physical States in d=3,N=2 Supergravity
To clarify some issues raised by D'Eath's recent proposal for the physical
states of supergravity in four dimensions, we study pure (topological)
supergravity in three dimensions, which is formally very similar, but
much easier to solve. The wave functionals solving the quantum constraints can
be understood in terms of arbitrary functions on the space of moduli and
supermoduli, which is not Hausdorff. We discuss the implications for the wave
functionals and show that these are not amenable to expansions in fermionic
coordinates, but can serve as lowest-order solutions to the quantum constraints
in an expansion in in more realistic theories.Comment: 11 pages, Report DESY 93-125, THU-93/1
Monodromy Matrix in the PP-Wave Limit
We construct the monodromy matrix for a class of gauged WZWN models in the
plane wave limit and discuss various properties of such systems.Comment: 16 page
Two-loop finiteness of D=2 supergravity
We establish two-loop (on shell) finiteness of certain supergravity theories
in two dimensions. Possible implications of this result are discussedComment: 11 page
An exceptional geometry for d=11 supergravity?
We analyze the algebraic constraints of the generalized vielbein in SO(1,2) x
SO(16) invariant d=11 supergravity, and show that the bosonic degrees of
freedom of d=11 supergravity, which become the physical ones upon reduction to
d=3, can be assembled into an E_8-valued vielbein already in eleven dimensions.
A crucial role in the construction is played by the maximal nilpotent commuting
subalgebra of E_8, of dimension 36, suggesting a partial unification of general
coordinate and tensor gauge transformations.Comment: 16 pages, LaTeX2
AdS vacua and RG flows in three dimensional gauged supergravities
We study supersymmetric vacua in N=4 and N=8, three dimensional
gauged supergravities, with scalar manifolds and , non-semisimple Chern-Simons
gaugings and ,
respectively. These are in turn equivalent to SO(4) and
Yang-Mills theories coupled to supergravity. For the N=4 case, we study
renormalization group flows between UV and IR vacua with the same
amount of supersymmetry: in one case, with (3,1) supersymmetry, we can find an
analytic solution whereas in another, with (2,0) supersymmetry, we give a
numerical solution. In both cases, the flows turn out to be v.e.v. flows, i.e.
they are driven by the expectation value of a relevant operator in the dual
. These provide examples of v.e.v. flows between two vacua
within a gauged supergravity framework.Comment: 35 pages in JHEP form, 3 figures, typos corrected, references adde
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