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

Physical States in d=3,N=2 Supergravity

To clarify some issues raised by D'Eath's recent proposal for the physical states of $N=1$ supergravity in four dimensions, we study pure (topological) $N=2$ 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 $\hbar$ in more realistic theories.Comment: 11 pages, Report DESY 93-125, THU-93/1

Generalized gaugings and the field-antifield formalism

We discuss the algebra of general gauge theories that are described by the embedding tensor formalism. We compare the gauge transformations dependent and independent of an invariant action, and argue that the generic transformations lead to an infinitely reducible algebra. We connect the embedding tensor formalism to the field-antifield (or Batalin-Vilkovisky) formalism, which is the most general formulation known for general gauge theories and their quantization. The structure equations of the embedding tensor formalism are included in the master equation of the field-antifield formalism.Comment: 42 pages; v2: some clarifications and 1 reference added; version to be published in JHE

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

Design of fibre reinforced PV concepts for building integrated applications

Fibre reinforced polymers present an interesting encapsulation medium for PV-modules. Glass fibres can provide increased strength and stiffness to thin polymer layers overcoming the brittleness and limited deformability of glass-panes. Glass fibre reinforced polymers allows for transparency over a broad range of the solar spectrum while the material properties and integral production processes create possibilities for novel product concepts with embedded PV technology. To explore such possibilities, innovative design methods were used to design novel PV product concepts for applications in the build environment.\ud In our paper three conceptual designs are presented; (1) a thin film module with an adjoining interconnection system functioning as structural element for geodetic roofing structures, (2) a PV lamella with single-axis tracking utilizing a linear concentration effect caused by the geometry of the product and the materials applied, and (3) a prepreg PV-material which allows for easy shaping during the production of PV modules with complex geometries. Each concept employs a specific PV technology and demonstrates a possible application aimed at a specific market. In this way we show the potential of integration of PV technology in fibre reinforced composites. The paper will be illustrated by concept renderings

Geometry of The Embedding of Supergravity Scalar Manifolds in D=11 and D=10

Several recent papers have made considerable progress in proving the existence of remarkable consistent Kaluza-Klein sphere reductions of D=10 and D=11 supergravities, to give gauged supergravities in lower dimensions. A proof of the consistency of the full gauged SO(8) reduction on S^7 from D=11 was given many years ago, but from a practical viewpoint a reduction to a smaller subset of the fields can be more manageable, for the purposes of lifting lower-dimensional solutions back to the higher dimension. The major complexity of the spherical reduction Ansatze comes from the spin-0 fields, and of these, it is the pseudoscalars that are the most difficult to handle. In this paper we address this problem in two cases. One arises in a truncation of SO(8) gauged supergravity in four dimensions to U(1)^4, where there are three pairs of dilatons and axions in the scalar sector. The other example involves the truncation of SO(6) gauged supergravity in D=5 to a subsector containing a scalar and a pseudoscalar field, with a potential that admits a second supersymmetric vacuum aside from the maximally-supersymmetric one. We briefly discuss the use of these emdedding Ansatze for the lifting of solutions back to the higher dimension.Comment: Latex, 24 pages, typos correcte

Forests and climate change: adaptation and mitigation

ETFRN news No. 50: Forests and Climate Change: adaptation and mitigation. This newsletter contains interesting materials for those who think about the question how to proceed with forests and climate change after Copenhagen, with or without an agreement. Here below are presented some observations from this newsletter: • Adaptation and mitigation are separate issues in the climate discussions, but in forest practice they are two sides of the same coin. • We need forest management directed at the realization of different objectives at the same time, we do not need pure ‘carbon forests’. Not addressing ‘people’ and ‘planet’ considerations is increasingly seen – by both the public and private sector – as a business risk. • Not all countries will be able to comply with REDD rules in the short term. The voluntary carbon market will remain important. • REDD is an opportunity and a risk for local communities. Risks should be made transparent, and open and equal participation by communities in design and decision-making should be promoted • REDD and other forest-based climate change mitigation measures are likely to be low-cost and effective in the short to medium term. Some stakeholders fear that forests may become a too-cheap mitigation option and corrupt the overall climate agreement. In most calculations, however, the costs of developing, operating and managing the institutional system required to produce credible and sustainable forest carbon credits are not internalized in forest carbon prices. If they were, forest carbon prices would become much higher and more realistic. • The role of forests must be clarified and articulated in National Adaptation Programs of Action (NAPAs). At present most political attention and financing is focused on REDD, and, in general, on climate mitigation. Only recently has the concern for the role of forests in adaptation gained ground; this emanates from the growing recognition that climate change will happen anyway. Moreover, climate change will affect the most vulnerable ecosystems and poorer regions. • There is a clear need for harmonization and coherence in the certification market (SFM, and carbon, fair trade etc.). Certification is not necessarily the only credible basis for payment. As illustrated in this issue, mutual trust can be an alternative, particularly for small-scale initiatives that cannot afford the high transaction costs of certification