8,944 research outputs found
Elaboration of the Model of Formation of Readiness of Future Primary School Teachers to the Use of Learning-playing Technologies
The study characterizes the structural-functional model of formation of readiness of students of the specialty “Primary education” to using learning-playing technologies in the educational process. Among general modeling forms there was chosen the combined model (graphic descriptive scheme) of the structural-functional type. There was substantiated the main idea of modeling of the process of formation of future primary school teachers' readiness to using learning-playing technologies, especially, elaboration of such structural-functional model that would allow to improve the effectiveness of this process, to make it correspondent to social requirements and expectations from realization of New Ukrainian school principles. It was determined, that the object of modeling is the process of formation of readiness to using learning-playing technologies, realized within the general system of the professional training of future primary school teachers. The aim of the model creation was formulated: elaboration of the schematic construction that embodies the abstract structure and the real projected process and result. The theoretical-methodological approaches to the model projecting process were separated, namely: system, activity, personally oriented, competence. The main blocs of the elaborated structural-functional model were separated, especially, target, content, procedural and resulting
Classical Spinning Branes in Curved Backgrounds
The dynamics of a classical branelike object in a curved background is
derived from the covariant stress-energy conservation of the brane matter. The
world sheet equations and boundary conditions are obtained in the pole-dipole
approximation, where nontrivial brane thickness gives rise to its intrinsic
angular momentum. It is shown that intrinsic angular momentum couples to both,
the background curvature and the brane orbital degrees of freedom. The whole
procedure is manifestly covariant with respect to spacetime diffeomorphisms and
world sheet reparametrizations. In addition, two extra gauge symmetries are
discovered and utilized. The examples of the point particle and the string in 4
spacetime dimensions are analyzed in more detail. A particular attention is
paid to the Nambu-Goto string with massive spinning particles attached to its
ends
Orbital magnetic moments in insulating Dirac systems: Impact on magnetotransport in graphene van der Waals heterostructures
In honeycomb Dirac systems with broken inversion symmetry, orbital magnetic
moments coupled to the valley degree of freedom arise due to the topology of
the band structure, leading to valley-selective optical dichroism. On the other
hand, in Dirac systems with prominent spin-orbit coupling, similar orbital
magnetic moments emerge as well. These moments are coupled to spin, but
otherwise have the same functional form as the moments stemming from spatial
inversion breaking. After reviewing the basic properties of these moments,
which are relevant for a whole set of newly discovered materials, such as
silicene and germanene, we study the particular impact that these moments have
on graphene nanoengineered barriers with artificially enhanced spin-orbit
coupling. We examine transmission properties of such barriers in the presence
of a magnetic field. The orbital moments are found to manifest in transport
characteristics through spin-dependent transmission and conductance, making
them directly accessible in experiments. Moreover, the Zeeman-type effects
appear without explicitly incorporating the Zeeman term in the models, i.e., by
using minimal coupling and Peierls substitution in continuum and the
tight-binding methods, respectively. We find that a quasiclassical view is able
to explain all the observed phenomena
Spin-valley filtering in strained graphene structures with artificially induced carrier mass and spin-orbit coupling
The interplay of massive electrons with spin-orbit coupling in bulk graphene
results in a spin-valley dependent gap. Thus, a barrier with such properties
can act as a filter, transmitting only opposite spins from opposite valleys. In
this Letter we show that strain induced pseudomagnetic field in such a barrier
will enforce opposite cyclotron trajectories for the filtered valleys, leading
to their spatial separation. Since spin is coupled to the valley in the
filtered states, this also leads to spin separation, demonstrating a
spin-valley filtering effect. The filtering behavior is found to be
controllable by electrical gating as well as by strain
Quantum freeze of fidelity decay for chaotic dynamics
We show that the mechanism of quantum freeze of fidelity decay for
perturbations with zero time-average, recently discovered for a specific case
of integrable dynamics [New J. Phys. 5 (2003) 109], can be generalized to
arbitrary quantum dynamics. We work out explicitly the case of chaotic
classical counterpart, for which we find semi-classical expressions for the
value and the range of the plateau of fidelity. After the plateau ends, we find
explicit expressions for the asymptotic decay, which can be exponential or
Gaussian depending on the ratio of the Heisenberg time to the decay time.
Arbitrary initial states can be considered, e.g. we discuss coherent states and
random states.Comment: 4 pages, 3 ps figures ; v2 corrected mistake in formula for t_
Directional States of Symmetric-Top Molecules Produced by Combined Static and Radiative Electric Fields
We show that combined electrostatic and radiative fields can greatly amplify
the directional properties, such as axis orientation and alignment, of
symmetric top molecules. In our computational study, we consider all four
symmetry combinations of the prolate and oblate inertia and polarizability
tensors, as well as the collinear and perpendicular (or tilted) geometries of
the two fields. In, respectively, the collinear or perpendicular fields, the
oblate or prolate polarizability interaction due to the radiative field forces
the permanent dipole into alignment with the static field. Two mechanisms are
found to be responsible for the amplification of the molecules' orientation,
which ensues once the static field is turned on: (a) permanent-dipole coupling
of the opposite-parity tunneling doublets created by the oblate polarizability
interaction in collinear static and radiative fields; (b) hybridization of the
opposite parity states via the polarizability interaction and their coupling by
the permanent dipole interaction to the collinear or perpendicular static
field. In perpendicular fields, the oblate polarizability interaction, along
with the loss of cylindrical symmetry, is found to preclude the wrong-way
orientation, causing all states to become high-field seeking with respect to
the static field. The adiabatic labels of the states in the tilted fields
depend on the adiabatic path taken through the parameter space comprised of the
permanent and induced-dipole interaction parameters and the tilt angle between
the two field vectors
Initial-state randomness as a universal source of decoherence
We study time evolution of entanglement between two qubits, which are part of
a larger system, after starting from a random initial product state. We show
that, due to randomness in the initial product state, entanglement is present
only between directly coupled qubits and only for short times. Time dependence
of the entanglement appears essentially independent of the specific hamiltonian
used for time evolution and is well reproduced by a parameter-free two-body
random matrix model.Comment: 8 pages, 6 figure
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