2,508 research outputs found
On T-duality in dilatonic gravity
Under the assumption of axial symmetry we introduce a map from dilatonic
gravity to a string-like action. This map allows one to introduce, in a rather
simple way, the equivalent of string theory T-duality in dilatonic gravity.
Here we choose the duality group to be an group and, for a particular
rotation, we recover a symmetry of dilatonic gravity discussed previously in
the literature.Comment: 10 pages, phyzz
Generalized Mathai-Quillen topological sigma models
A simple field theoretical approach to Mathai-Quillen topological field theories of maps X: M_I\rightarrow M_T from an internal space to a target space is presented. An operator that is closely related to the topological charge Q is introduced. This operator turns out to be a very convenient tool for studying the geometrical properties of the theory on the target space. As an example of applications of our formalism we compute by applying our formulas the action and Q-variations of the fields of two well known topological systems: Topological Quantum Mechanics and type-A topological Sigma Model
Development and validation of a building design waste reduction model
Reduction in construction waste is a pressing need in many countries. The design of building elements is considered a pivotal process to achieve waste reduction at source, which enables an informed prediction of their wastage reduction levels. However the lack of quantitative methods linking design strategies to waste reduction hinders designing out waste practice in building projects. Therefore, this paper addresses this knowledge gap through the design and validation of a Building Design Waste Reduction Strategies (Waste ReSt) model that aims to investigate the relationships between design variables and their impact on onsite waste reduction. The Waste ReSt model was validated in a real-world case study involving 20 residential buildings in Spain. The validation process comprises three stages. Firstly, design waste causes were analyzed. Secondly, design strategies were applied leading to several alternative low waste building elements. Finally, their potential source reduction levels were quantified and discussed within the context of the literature. The Waste ReSt model could serve as an instrumental tool to simulate designing out strategies in building projects. The knowledge provided by the model could help project stakeholders to better understand the correlation between the design process and waste sources and subsequently implement design practices for low-waste buildings
On N=1 Superconformal Algebra in the Non-Critical Bosonic String Theory
In a recent work it has been shown that the bosonic strings could be embedded
into a special class of fermionic strings. We argue that the
superpartners of any physical state in the spectrum of this fermionic string is
non-physical. So, there is no supersymmetry in the space of physical states and
the embedding is, in this sense, ``trivial''. We here propose two different
constructions as possible candidates of non-trivial embeddings of the
non-critical bosonic strings into some special class of fermionic strings
of which one is the non-critical NSR string. The BRST charge of the
fermionic strings in both cases decompose as ,
where is the BRST charge of the bosonic string.Comment: 12 pages, Plain tex, UG-2/9
S-Duality, SL(2,Z) Multiplets and Killing Spinors
The S-duality transformations in type IIB string theory can be seen as local
U(1) transformations in type IIB supergravity. We use this approach to
construct the multiplets associated to supersymmetric backgrounds of
type IIB string theory and the transformation laws of their corresponding
Killing spinors.Comment: 13 pages, Harvma
String Theory as a Constrained Topological Sigma Model
It has been argued by Ishikawa and Kato that by making use of a specific
bosonization, string theory can be regarded as a constrained
topological sigma model. We generalize their construction for any
minimal model coupled to two dimensional (2d) gravity and show that the
energy--momentum tensor and the topological charge of a constrained topological
sigma model can be mapped to the energy--momentum tensor and the BRST charge of
string theory at zero cosmological constant. We systematically study
the physical state spectrum of this topological sigma model and recover the
spectrum in the absolute cohomology of string theory. This procedure
provides us a manifestly topological representation of the continuum Liouville
formulation of string theory.Comment: 12 pages, Latex file, UG-9/9
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