3,478 research outputs found
A general approximation of quantum graph vertex couplings by scaled Schroedinger operators on thin branched manifolds
We demonstrate that any self-adjoint coupling in a quantum graph vertex can
be approximated by a family of magnetic Schroedinger operators on a tubular
network built over the graph. If such a manifold has a boundary, Neumann
conditions are imposed at it. The procedure involves a local change of graph
topology in the vicinity of the vertex; the approximation scheme constructed on
the graph is subsequently `lifted' to the manifold. For the corresponding
operator a norm-resolvent convergence is proved, with the natural
identification map, as the tube diameters tend to zero.Comment: 19 pages, one figure; introduction amended and some references added,
to appear in CM
Expanding Autonomy Psychological Need States From Two (Satisfaction, Frustration) to Three (Dissatisfaction): A Classroom-Based Intervention Study
We propose that students experience "autonomy dissatisfaction" when the learning environment is indifferent to their psychological need for autonomy. We hypothesized that (a) students could distinguish this newly proposed need state from both autonomy satisfaction and autonomy frustration, (b) autonomy dissatisfaction would explain unique and rather substantial variance in students' classroom disengagement, and (c) a full understanding of the psychological need for autonomy necessitates expanding the current emphasis from two need states (satisfaction, frustration) to three (dissatisfaction). In the experimental condition, 20 secondaryschool physical education (PE) teachers learned how to teach in an autonomy-supportive way; in the control condition, 17 PE teachers taught using "practice as usual." Their 2,669 students (1,180 females, 1,489 males) self-reported their autonomy satisfaction, autonomy dissatisfaction, autonomy frustration, engagement, and disengagement throughout a semester. Objective raters scored the manipulation check (teachers' autonomysupportive instructional behaviors) and the engagement-disengagement outcome measure. Autonomy dissatisfaction longitudinally increased in the control group and longitudinally decreased in the experimental group. Most importantly, intervention-enabled decreases in autonomy dissatisfaction decreased students' end-ofsemester disengagement, even after controlling for midsemester changes in autonomy satisfaction and autonomy frustration. We discuss the theoretical and practical benefits of adding autonomy dissatisfaction to the self-determination theory explanatory framework
Characterization of a novel reassortant H5N6 highly pathogenic avian influenza virus clade 2.3.4.4 in Korea, 2017
Nuclear Mass Dependence of Chaotic Dynamics in Ginocchio Model
The chaotic dynamics in nuclear collective motion is studied in the framework
of a schematic shell model which has only monopole and quadrupole degrees of
freedom. The model is shown to reproduce the experimentally observed global
trend toward less chaotic motion in heavier nuclei. The relation between
current approach and the earlier studies with bosonic models is discussed.Comment: 11 Page REVTeX file, 2 postscript figures, uuencode
Above-Room-Temperature Ferromagnetism in GaSb/Mn Digital Alloys
Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy.
Transmission electron micrographs showed good crystal quality with individual
Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was
seen in as-grown samples. All samples studied exhibited ferromagnetism with
temperature dependent hysteresis loops in the magnetization accompanied by
metallic p-type conductivity with a strong anomalous Hall effect (AHE) up to
400 K (limited by the experimental setup). The anomalous Hall effect shows
hysteresis loops at low temperatures and above room temperature very similar to
those seen in the magnetization. The strong AHE with hysteresis indicates that
the holes interact with the Mn spins above room temperature. All samples are
metallic, which is important for spintronics applications.
* To whom correspondence should be addressed. E-mail: [email protected]
Relation between the 4d superconformal index and the S^3 partition function
A relation between the 4d superconformal index and the S^3 partition function
is studied with focus on the 4d and 3d actions used in localization. In the
case of vanishing Chern-Simons levels and round S^3 we explicitly show that the
3d action is obtained from the 4d action by dimensional reduction up to terms
which do not affect the exact results. By combining this fact and a recent
proposal concerning a squashing of S^3 and SU(2) Wilson line, we obtain a
formula which gives the partition function depending on the Weyl weight of
chiral multiplets, real mass parameters, FI parameters, and a squashing
parameter as a limit of the index of a parent 4d theory.Comment: 20 pages, LaTeX; v2: comments added; v3: minor corrections, version
published in JHE
Duality between N=5 and N=6 Chern-Simons matter theory
We provide evidences for the duality between Chern-Simons matter theory and theory for a suitable by working out the
superconformal index, which shows perfect matching. For theories,
we show that supersymmetry is enhanced to by explicitly
constructing monopole operators filling in -currents. Finally we
work out the large index of and show that
it exactly matches with the gravity index on , which
further provides additional evidence for the duality between the
and theory for Comment: 15 pages; references adde
Spectral properties on a circle with a singularity
We investigate the spectral and symmetry properties of a quantum particle
moving on a circle with a pointlike singularity (or point interaction). We find
that, within the U(2) family of the quantum mechanically allowed distinct
singularities, a U(1) equivalence (of duality-type) exists, and accordingly the
space of distinct spectra is U(1) x [SU(2)/U(1)], topologically a filled torus.
We explore the relationship of special subfamilies of the U(2) family to
corresponding symmetries, and identify the singularities that admit an N = 2
supersymmetry. Subfamilies that are distinguished in the spectral properties or
the WKB exactness are also pointed out. The spectral and symmetry properties
are also studied in the context of the circle with two singularities, which
provides a useful scheme to discuss the symmetry properties on a general basis.Comment: TeX, 26 pages. v2: one reference added and two update
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