1,172 research outputs found
Orbitally-driven Peierls state in spinels
We consider the superstructures, which can be formed in spinels containing on
B-sites the transition-metal ions with partially filled t2g levels. We show
that, when such systems are close to itinerant state (e.g. have an
insulator-metal transition), there may appear in them an orbitally-driven
Peierls state. We explain by this mechanism the very unusual superstructures
observed in CuIr2S4 (octamers) and MgTi2O4 (chiral superstructures) and suggest
that similar phenomenon should be observed in NaTiO2 and possibly in some other
systems.Comment: 4 pages, 3 figure
"Flip" of SL(2,R)-duality in five-dimensional supergravity
The dimensional reduction of the bosonic sector of five-dimensional minimal
supergravity to a Lorentzian four-dimensional spacetime leads to a theory with
a massless axion and a dilaton coupled to gravity and two U(1) gauge fields and
the dimensionally reduced equations of motion have SL(2,R)/SO(2)-duality
invariance. In our previous work, utilizing the duality invariance, we
formulated solution-generation techniques within five-dimensional minimal
supergravity. In this work, by choosing a timelike Killing vector, we consider
dimensional reduction to a four-dimensional Euclidean space, in which the field
equations have SL(2,R)/SO(1,1) invariance. In the timelike case, we develop a
new duality transformation technique, while in the spacelike case we have done
that in the previous work. As an example, by applying it to the Rasheed
solutions, we obtain rotating Kaluza-Klein black hole solutions in
five-dimensional minimal supergravity. In general, in contrast to the spacelike
case, the resulting dimensionally reduced solution includes the so-called NUT
parameter and therefore from a four-dimensional point of view, such a spacetime
is not asymptotically flat. However, it is shown that in some special cases, it
can describe ordinary Kaluza-Klein black holes.Comment: 16 page
Coulomb wave function correction including momentum resolution for charged hadron pairs : Analysis of data of πz π{ pair in p + Ta reaction at 70 GeV/c
We propose a new method for the Coulomb wave function correction including the momentum resolution for charged hadron pairs and apply it to the precise data on πz π{ correlations obtained in p + Ta reaction at 70 GeV/c. It is found that interaction regions of this reaction (assuming Gaussian source function) are 5.6 ± 3.0 and 4.4 ± 2.6 fm for the thicknesses of the target 8 and 1.4 microns, respectively. The physical picture of the source size obtained in this way is discussed.Article信州大学理学部紀要 31(2): 81-88(1997)departmental bulletin pape
New approach to solution generation using SL(2,R)-duality of a dimensionally reduced space in five-dimensional minimal supergravity and new black holes
The dimensional reduction of (the bosonic sector of) five-dimensional minimal
supergravity to four dimensions leads to a theory with a massless axion and a
dilaton coupled to gravity and two U(1) gauge fields (one of which has
Chern-Simons coupling), whose field equations have SL(2,R)-invariance.
Utilizing this SL(2,R)-duality, we provide a new formalism for solution
generation. As an example, applying it to the Rasheed solution, which are known
to describe dyonic rotating black holes (from the four-dimensional point of
view) of five-dimensional pure gravity, we obtain rotating Kaluza-Klein black
hole solutions in five-dimensional minimal supergravity. We also show that the
solutions have six charges: mass, angular momentum, Kaluza-Klein
electric/magnetic charges and electric/magnetic charges of the Maxwell field,
four of which are related by a constraint.Comment: 17 pages, a few references and comments added, to be published in PR
Proximal business intelligence on the semantic web
This is the post-print version of this article. The official version can be accessed from the link below - Copyright @ 2010 Springer.Ubiquitous information systems (UBIS) extend current Information System thinking to explicitly differentiate technology between devices and software components with relation to people and process. Adapting business data and management information to support specific user actions in context is an ongoing topic of research. Approaches typically focus on providing mechanisms to
improve specific information access and transcoding but not on how the information
can be accessed in a mobile, dynamic and ad-hoc manner. Although web ontology has been used to facilitate the loading of data warehouses, less research has been carried out on ontology based mobile reporting. This paper explores how business data can be modeled and accessed using the web ontology
language and then re-used to provide the invisibility of pervasive access; uncovering
more effective architectural models for adaptive information system strategies of this type. This exploratory work is guided in part by a vision of business intelligence that is highly distributed, mobile and fluid, adapting to sensory understanding of the underlying environment in which it operates. A proof-of concept mobile and ambient data access architecture is developed in order to further test the viability of such an approach. The paper concludes with an ontology engineering framework for systems of this type – named UBIS-ONTO
On the sigma-model structure of type IIA supergravity action in doubled field approach
In this letter we describe how to string together the doubled field approach
by Cremmer, Julia, Lu and Pope with Pasti-Sorokin-Tonin technique to construct
the sigma-model-like action for type IIA supergravity. The relation of the
results with that of obtained in the context of searching for
Superstring/M-theory hidden symmetry group is discussed.Comment: 9 pp, LATEX; published in JETP Let
Free boson formulation of boundary states in W_3 minimal models and the critical Potts model
We develop a Coulomb gas formalism for boundary conformal field theory having
a symmetry and illustrate its operation using the three state Potts model.
We find that there are free-field representations for six conserving
boundary states, which yield the fixed and mixed physical boundary conditions,
and two violating boundary states which yield the free and new boundary
conditions. Other violating boundary states can be constructed but they
decouple from the rest of the theory. Thus we have a complete free-field
realization of the known boundary states of the three state Potts model. We
then use the formalism to calculate boundary correlation functions in various
cases. We find that the conformal blocks arising when the two point function of
is calculated in the presence of free and new boundary conditions
are indeed the last two solutions of the sixth order differential equation
generated by the singular vector.Comment: 25 page
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