35,163 research outputs found
Large-small dualities between periodic collapsing/expanding branes and brane funnels
We consider space and time dependent fuzzy spheres arising in
intersections in IIB string theory and collapsing D(2p)-branes in
IIA string theory.
In the case of , where the periodic space and time-dependent solutions
can be described by Jacobi elliptic functions, there is a duality of the form
to which relates the space and time dependent solutions.
This duality is related to complex multiplication properties of the Jacobi
elliptic functions. For funnels, the description of the periodic space
and time dependent solutions involves the Jacobi Inversion problem on a
hyper-elliptic Riemann surface of genus 3. Special symmetries of the Riemann
surface allow the reduction of the problem to one involving a product of genus
one surfaces. The symmetries also allow a generalisation of the to duality. Some of these considerations extend to the case of the
fuzzy .Comment: Latex, 50 pages, 2 figures ; v2 : a systematic typographical error
corrected + minor change
A Declarative Semantics for CLP with Qualification and Proximity
Uncertainty in Logic Programming has been investigated during the last
decades, dealing with various extensions of the classical LP paradigm and
different applications. Existing proposals rely on different approaches, such
as clause annotations based on uncertain truth values, qualification values as
a generalization of uncertain truth values, and unification based on proximity
relations. On the other hand, the CLP scheme has established itself as a
powerful extension of LP that supports efficient computation over specialized
domains while keeping a clean declarative semantics. In this paper we propose a
new scheme SQCLP designed as an extension of CLP that supports qualification
values and proximity relations. We show that several previous proposals can be
viewed as particular cases of the new scheme, obtained by partial
instantiation. We present a declarative semantics for SQCLP that is based on
observables, providing fixpoint and proof-theoretical characterizations of
least program models as well as an implementation-independent notion of goal
solutions.Comment: 17 pages, 26th Int'l. Conference on Logic Programming (ICLP'10
Quantum canonical tensor model and an exact wave function
Tensor models in various forms are being studied as models of quantum
gravity. Among them the canonical tensor model has a canonical pair of
rank-three tensors as dynamical variables, and is a pure constraint system with
first-class constraints. The Poisson algebra of the first-class constraints has
structure functions, and provides an algebraically consistent way of
discretizing the Dirac first-class constraint algebra for general relativity.
This paper successfully formulates the Wheeler-DeWitt scheme of quantization of
the canonical tensor model; the ordering of operators in the constraints is
determined without ambiguity by imposing Hermiticity and covariance on the
constraints, and the commutation algebra of constraints takes essentially the
same from as the classical Poisson algebra, i.e. is first-class. Thus one could
consistently obtain, at least locally in the configuration space, wave
functions of "universe" by solving the partial differential equations
representing the constraints, i.e. the Wheeler-DeWitt equations for the quantum
canonical tensor model. The unique wave function for the simplest non-trivial
case is exactly and globally obtained. Although this case is far from being
realistic, the wave function has a few physically interesting features; it
shows that locality is favored, and that there exists a locus of configurations
with features of beginning of universe.Comment: 17 pages. Section 2 expanded to include fuzzy-space interpretation,
and other minor change
Giant Gravitons in type IIA PP-wave Background
We examine giant gravitons with a worldvolume magnetic flux in type IIA
pp-wave background and find that they can move away from the origin along
direction in target space satisfying . This nontrivial relation can be
regarded as a complementary relation of the giant graviton on IIA pp-wave and
is shown to be connected to the spacetime uncertainty principle. The giant
graviton is also investigated in a system of N D0-branes as a fuzzy sphere
solution. It is observed that enters into the fuzzy algebra as a
deformation parameter. Such a background dependent Myers effect guarantees that
we again get the crucial relation of our giant graviton. In the paper, we also
find a BIon configuration on the giant graviton in this background.Comment: 10 pages, no figure, content added, typo corrected, reference adde
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