19,455 research outputs found
Geometry versus Entanglement in Resonating Valence Bond Liquids
We investigate the behavior of bipartite as well as genuine multipartite
entanglement of a resonating valence bond state on a ladder. We show that the
system possesses significant amounts of bipartite entanglement in the steps of
the ladder while no substantial bipartite entanglement is present in the rails.
Genuine multipartite entanglement present in the system is negligible. The
results are in stark contrast with the entanglement properties of the same
state on isotropic lattices in two and higher dimensions, indicating that the
geometry of the lattice can have important implications on the quality of
quantum information and other tasks that can be performed by using multiparty
states on that lattice.Comment: 6 pages, 8 figures, RevTeX
Patterns in Open String Field Theory Solutions
In open string field theory the kinetic operator mixes matter and ghost
sectors, and thus the ghost structure of classical solutions is not universal.
Nevertheless, we have found from numerical analysis that certain ratios of
expectation values for states involving pure ghost excitations appear to be
universal. We give an analytic expression for these ratios and find good
evidence that they are common to all known solutions of open string field
theory, including the tachyon vacuum solution, lump solutions and string fields
representing marginal deformations. We also draw attention to a close
correspondence between the expectation values for the pure matter components in
the tachyon vacuum solution and those in the solution of a simpler equation for
a ghost number zero string field. Finally we observe that the action of L_0 on
the tachyon condensate gives a state that is approximately factorized into a
matter and a ghost part.Comment: 21 pages, LaTe
On Orientifold Constructions of Type IIA Dual Pairs
In this paper we analyze the earlier constructions of the type IIA dual pairs
through orientifolding. By an appropriate choice of -matrix basis for
the spinor representations of the -duality group, we give an explicit
relationship between the orientifold models and their dual pairs.Comment: 11pages, Late
Sen and the art of educational maintenance: evidencing a capability, as opposed to an effectiveness, approach to schooling
There are few more widely applied terms in common parlance than âcapabilityâ. It is used (inaccurately) to represent everything from the aspiration to provide opportunity to notions of innate academic ability, with everything in between claiming apostolic succession to Amartya Sen, who (with apologies to Aristotle) first developed the concept. This paper attempts to warrant an adaptation of Senâs capability theory to schooling and schooling policy, and to proof his concepts in the new setting using research involving 100 pupils from 5 English secondary schools and a schedule of questions derived from the capability literature. The findings suggest that a capability approach can provide an alternative to the dominant Benthamite school effectiveness paradigm, and can offer a sound theoretical framework for understanding better the assumed relationship between schooling and well-being
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