3,092 research outputs found
Coherent-state quantization of constrained fermion systems
The quantization of systems with first- and second-class constraints within
the coherent-state path-integral approach is extended to quantum systems with
fermionic degrees of freedom. As in the bosonic case the importance of
path-integral measures for Lagrange multipliers, which in this case are in
general expected to be elements of a Grassmann algebra, is emphasized. Several
examples with first- and second-class constraints are discussed.Comment: LaTeX 2e, Springer macro pljour2, 11 pages, to appear in Z. Phys.
Roll tracking effects of G-vector tilt and various types of motion washout
In a dogfight scenario, the task was to follow the target's roll angle while suppressing gust disturbances. All subjects adopted the same behavioral strategies in following the target while suppressing the gusts, and the MFP-fitted math model response was generally within one data symbol width. The results include the following: (1) comparisons of full roll motion (both with and without the spurious gravity tilt cue) with the static case. These motion cues help suppress disturbances with little net effect on the visual performance. Tilt cues were clearly used by the pilots but gave only small improvement in tracking errors. (2) The optimum washout (in terms of performance close to real world, similar behavioral parameters, significant motion attenuation (60 percent), and acceptable motion fidelity) was the combined attenuation and first-order washout. (3) Various trends in parameters across the motion conditions were apparent, and are discussed with respect to a comprehensive model for predicting adaptation to various roll motion cues
Hohenberg-Kohn theorem for the lowest-energy resonance of unbound systems
We show that under well-defined conditions the Hohenberg-Kohn theorem (HKT)
can be extended to the lowest-energy resonance of unbound systems. Using the
Gel'fand Levitan theorem, the extended version of the HKT can also be applied
to systems that support a finite number of bound states. The extended version
of the HKT provides an adequate framework to carry out DFT calculations of
negative electron affinities.Comment: 4 pages, 3 figure
Social pedagogical perspectives on fidelity to a manual: Professional principles and dilemmas in everyday expertise
Manualised interventions, in use across the UK for decades and increasingly in use in Denmark, aim
to support change through professional practitioners following detailed prescriptions of what they must
do to affect a particular change in the target group. Social pedagogy, a strong professional tradition in
Denmark and an emerging profession in the UK, takes an approach that responds to the individual’s
experience of the immediate situation, seeks to nurture relational opportunities and to empower people
to fully participate in their lives and society. Harbo’s research reveals that this approach can be at odds
with manualised interventions for a variety of reasons. A social pedagogically informed programme
has been developed in London that uses a clear ethical stance and key theories as its foundation, and
upon which structures have been developed, but no manual. This article explores the use of these
manualised and non-manualised interventions in Denmark and the UK and the roles of social pedagogues
in supporting change through programmatic interventions. Harbo’s doctoral research findings on practice surrounding the highly prescriptive manual Aggression Replacement Training in Denmark
(Harbo, 2019) is explored alongside Kemp’s reflections on the social pedagogically informed Family
Learning Intervention Programme in England, examining the tensions and synergies that emerge around
each programme when they meet reality and the individual characteristics of day-to-day situations.
The perspectives presented emerge from practice research and reflections, and as such are based in an
experiential research tradition. Finally, we draw together our learning and openings for further research
and policy development
Classical Supersymmetric Mechanics
We analyse a supersymmetric mechanical model derived from (1+1)-dimensional
field theory with Yukawa interaction, assuming that all physical variables take
their values in a Grassmann algebra B. Utilizing the symmetries of the model we
demonstrate how for a certain class of potentials the equations of motion can
be solved completely for any B. In a second approach we suppose that the
Grassmann algebra is finitely generated, decompose the dynamical variables into
real components and devise a layer-by-layer strategy to solve the equations of
motion for arbitrary potential. We examine the possible types of motion for
both bosonic and fermionic quantities and show how symmetries relate the former
to the latter in a geometrical way. In particular, we investigate oscillatory
motion, applying results of Floquet theory, in order to elucidate the role that
energy variations of the lower order quantities play in determining the
quantities of higher order in B.Comment: 29 pages, 2 figures, submitted to Annals of Physic
More on coupling coefficients for the most degenerate representations of SO(n)
We present explicit closed-form expressions for the general group-theoretical
factor appearing in the alpha-topology of a high-temperature expansion of
SO(n)-symmetric lattice models. This object, which is closely related to
6j-symbols for the most degenerate representation of SO(n), is discussed in
detail.Comment: 9 pages including 1 table, uses IOP macros Update of Introduction and
Discussion, References adde
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