Spin stiffness of a Fermi liquid in the ν = 1 quantum Hall regime
Anomalous behavior of spin stiffness is revealed in ZnO-based two-dimensional electron systems (2DESs)
with strong Coulomb interaction and Wigner-Seitz parameter r_s > 6. The spin stiffness is extracted directly from
the quadratic k-dispersion of spin excitons at ν = 1 probed by inelastic light scattering. The resulting values are
found to be dramatically rescaled compared to the case of weakly interacting 2DESs—spin stiffness turned out
to be of the order of the cyclotron energy with the effective mass of Fermi-liquid quasiparticles. This result is
also confirmed by the exact diagonalization simulations.
We analyze the role of local geometry in the spin and orbital interaction in transition metal compounds with orbital degeneracy. We stress that the tendency observed in the most studied case (transition metals in O6 octahedra with one common oxygen—common corner of neighboring octahedra—and with ~180° metal–oxygen–metal bonds), that ferro-orbital ordering renders antiferro-spin coupling and, vice versa, antiferro-orbitals give ferro-spin ordering, is not valid in the general case, in particular, for octahedra with a common edge and with ~90° M–O–M bonds. Special attention is paid to the “third case,” that of neighboring octahedra with a common face (three common oxygens), which has largely been disregarded until now, although there are many real systems with this geometry. Interestingly enough, the spin-orbit exchange in this case turns out to be simpler and more symmetric than in the first two cases. We also consider, which form the effective exchange takes for different geometries in the case of strong spin–orbit coupling.
Exchange interaction of electron and positron bunches is simulated using the particle-in-cell method and macroscopic electron and positron wave functions. It is shown that a periodic exchange process with low or high nonlinearity is realized during variations in the electron and positron concentrations.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.