3,390 research outputs found
Fidelity amplitude of the scattering matrix in microwave cavities
The concept of fidelity decay is discussed from the point of view of the
scattering matrix, and the scattering fidelity is introduced as the parametric
cross-correlation of a given S-matrix element, taken in the time domain,
normalized by the corresponding autocorrelation function. We show that for
chaotic systems, this quantity represents the usual fidelity amplitude, if
appropriate ensemble and/or energy averages are taken. We present a microwave
experiment where the scattering fidelity is measured for an ensemble of chaotic
systems. The results are in excellent agreement with random matrix theory for
the standard fidelity amplitude. The only parameter, namely the perturbation
strength could be determined independently from level dynamics of the system,
thus providing a parameter free agreement between theory and experiment
Interactional positioning and narrative self-construction in the first session of psychodynamic-interpersonal psychotherapy
The purpose of this study is to identify possible session one indicators of end of treatment psychotherapy outcome using the framework of three types of interactional positioning; clientâs self-positioning, clientâs positioning between narrated self and different partners, and the positioning between client and therapist. Three successful cases of 8-session psychodynamic-interpersonal (PI) therapy were selected on the basis of client Beck Depression Inventory scores. One unsuccessful case was also selected against which identified patterns could be tested. The successful clients were more descriptive about their problems and demonstrated active rapport-building, while the therapist used positionings expressed by the client in order to explore the positionings developed between them during therapy. The unsuccessful case was characterized by lack of positive self-comment, minimization of agentic self-capacity, and empathy-disrupting narrative confusions. We conclude that the theory of interactional positioning has been useful in identifying patterns worth exploring as early indicators of success in PI therapy
Academic achievement : the role of praise in motivating students
The motivation of students is an important issue in higher education, particularly in the context of the increasing diversity of student populations. A social-cognitive perspective assumes motivation to be dynamic, context-sensitive and changeable, thereby rendering it to be a much more differentiated construct than previously understood. This complexity may be perplexing to tutors who are keen to develop applications to improve academic achievement. One application that is within the control of the tutor, at least to some extent, is the use of praise. Using psychological literature the article argues that in motivating students, the tutor is not well served by relying on simplistic and common sense understandings of the construct of praise and that effective applications of praise are mediated by students' goal orientations, which of themselves may be either additive or interactive composites of different objectives and different contexts
The PERMA well-being model and music facilitation practice: Preliminary documentation for well-being through music provision in Australian schools
The aim of this study was to consider how we can invest in music-making to promote well-being in school contexts. Web-based data collection was conducted where researchers identified 17 case studies that describe successful music programs in schools in Australia. The researchers aligned content from these case studies into the five categories of the PERMA well-being model: Positive emotions, Engagement, Relationships, Meaning, and Accomplishment, in order to understand how each well-being element was realised through the music programs. The results indicate that the element of the PERMA well-being model that relates to relationships was described most often. Collaboration and partnership between students, teachers, and staff in schools, and local people in the community such as parents, local entrepreneurs, and musicians were repeatedly identified as a highly significant contributing factor in the success of the music program. The school leaders? roles in providing opportunities for students to experience musical participation and related activities (engagement) and valuing these experiences (meaning) were also crucial in the facilitation of the music programs. The findings of this study indicate that tailored music and relationship-centred music programs in schools not only increase skills and abilities of the students, but also improve the psychosocial well-being of the students and the community
Relativistic echo dynamics and the stability of a beam of Landau electrons
We extend the concepts of echo dynamics and fidelity decay to relativistic
quantum mechanics, specifically in the context of Klein-Gordon and Dirac
equations under external electromagnetic fields. In both cases we define
similar expressions for the fidelity amplitude under perturbations of these
fields, and a covariant version of the echo operator. Transformation properties
under the Lorentz group are established. An alternate expression for fidelity
is given in the Dirac case in terms of a 4-current. As an application we study
a beam of Landau electrons perturbed by field inhomogeneities.Comment: 8 pages, no figure
Universality of Level Spacing Distributions in Classical Chaos
We suggest that random matrix theory applied to a classical action matrix can
be used in classical physics to distinguish chaotic from non-chaotic behavior.
We consider the 2-D stadium billiard system as well as the 2-D anharmonic and
harmonic oscillator. By unfolding of the spectrum of such matrix we compute the
level spacing distribution, the spectral auto-correlation and spectral
rigidity. We observe Poissonian behavior in the integrable case and Wignerian
behavior in the chaotic case. We present numerical evidence that the action
matrix of the stadium billiard displays GOE behavior and give an explanation
for it. The findings present evidence for universality of level fluctuations -
known from quantum chaos - also to hold in classical physics
Spectral Density of the QCD Dirac Operator near Zero Virtuality
We investigate the spectral properties of a random matrix model, which in the
large limit, embodies the essentials of the QCD partition function at low
energy. The exact spectral density and its pair correlation function are
derived for an arbitrary number of flavors and zero topological charge. Their
microscopic limit provide the master formulae for sum rules for the inverse
powers of the eigenvalues of the QCD Dirac operator as recently discussed by
Leutwyler and Smilga.Comment: 9 pages + 1 figure, SUNY-NTG-93/
Flavor and Charge Symmetry in the Parton Distributions of the Nucleon
Recent calculations of charge symmetry violation(CSV) in the valence quark
distributions of the nucleon have revealed that the dominant symmetry breaking
contribution comes from the mass associated with the spectator quark
system.Assuming that the change in the spectator mass can be treated
perturbatively, we derive a model independent expression for the shift in the
parton distributions of the nucleon. This result is used to derive a relation
between the charge and flavor asymmetric contributions to the valence quark
distributions in the proton, and to calculate CSV contributions to the nucleon
sea. The CSV contribution to the Gottfried sum rule is also estimated, and
found to be small
Phase shift experiments identifying Kramers doublets in a chaotic superconducting microwave billiard of threefold symmetry
The spectral properties of a two-dimensional microwave billiard showing
threefold symmetry have been studied with a new experimental technique. This
method is based on the behavior of the eigenmodes under variation of a phase
shift between two input channels, which strongly depends on the symmetries of
the eigenfunctions. Thereby a complete set of 108 Kramers doublets has been
identified by a simple and purely experimental method. This set clearly shows
Gaussian unitary ensemble statistics, although the system is time-reversal
invariant.Comment: RevTex 4, 5 figure
Developing autonomous learning in first year university students using perspectives from positive psychology
Autonomous learning is a commonly occurring learning outcome from university study, and it is argued that students require confidence in their own abilities to achieve this. Using approaches from positive psychology, this study aimed to develop confidence in firstâyear university students to facilitate autonomous learning. Psychological character strengths were assessed in 214 students on day one at university. Two weeks later their top three strengths were given to them in study skills modules as part of a psychoâeducational intervention designed to increase their selfâefficacy and selfâesteem. The impact of the intervention was assessed against a control group of 40 students who had not received the intervention. The results suggested that students were more confident after the intervention, and that levels of autonomous learning increased significantly compared to the controls. Character strengths were found to be associated with selfâefficacy, selfâesteem and autonomous learning in ways that were theoretically meaningful
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