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We revisit the problem of diffusion in a driven system consisting of an inertial Brownian particle moving in a symmetric periodic potential and subjected to a symmetric time-periodic force. We reveal parameter domains in which diffusion is normal in the long time limit and exhibits intriguing giant damped quasiperiodic oscillations as a function of the external driving amplitude. As the mechanism behind this effect, we identify the corresponding oscillations of difference in the number of locked and running trajectories that carry the leading contribution to the diffusion coefficient. Our findings can be verified experimentally in a multitude of physical systems, including colloidal particles, Josephson junction, or cold atoms dwelling in optical lattices, to name only a few. [ABSTRACT FROM AUTHOR]

Continuous phase drift and thermal ordering of the Aharonov-Bohm oscillations in a small ring interferometer have been revealed by numerical calculation of the conductance. It has been found that the sign and rate of change in the oscillation amplitude with increasing temperature depend on the Fermi energy. The calculation results have been compared with the experimental data for the same sample. [ABSTRACT FROM AUTHOR]

We report the observation of the Fermi energy controlled redirection of the ballistic electron flow in a three-terminal system based on a small (100 nm) triangular quantum dot defined in a two-dimensional electron gas (2DEG). Measurement shows strong large-scale sign-changing oscillations of the partial conductance coefficient difference G21 - G23 on the gate voltage in zero magnetic field. Simple formulas and numerical simulation show that the effect can be explained by quantum interference and is associated with weak asymmetry of the dot or inequality of the ports connecting the dot to the 2DEG reservoirs. The effect may be strengthened by a weak perpendicular magnetic field. We also consider an additional three-terminal system in which the direction of the electron flow can be controlled by the voltage on the scanning gate microscopy (SGM) tip. [ABSTRACT FROM AUTHOR]

Oscillation frequencies of tetragonal ZnP 2 and CdP 2 crystal lattices are calculated for the Keating model. Results of numerical calculations of the phonon spectra in the most symmetric directions and at points of the Brillouin zones are presented. The calculated function of phonon frequency distribution is used to calculate the thermal capacity of CdP 2. [ABSTRACT FROM AUTHOR]

Ballistic transport in an open small (100 nm) three-terminal quantum dot has been analyzed. The dot is based on the high-mobility 2D electron gas of the AlGaAs/GaAs heterojunction. It has been shown that the gate oscillations of the resistance of such a dot arise due to the coherent scattering of electrons on its quasidiscrete levels and these oscillations are suppressed by a weak magnetic field. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Small-radius (110 nm) ring interferometers were fabricated by the local anodic oxidation of AlGaAs/GaAs heterostructures containing 2D electron gas. Measurements and modeling show that a small ring asymmetry, which is detected by an atomic force microscope, leads to a small amplitude of Aharonov–Bohm oscillations, while a stronger asymmetry completely suppresses these oscillations. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

In this paper. we suggest a modified mode-matching method that is applied to compute the S-matrices of T-junctions of rectangular waveguides with various inserts in the coupling region. We consider in detail how to compute an H-plane tee-junction with a separating plate in the straight arm. which is frequently used to divide linearly-polarized signals. This algorithm provides a good computation efficiency excluding the regions near to the irregular points corresponding to the eigen oscillations of the coupling domain with metallized walls. [ABSTRACT FROM AUTHOR]

An optically pumped submillimeter laser on a basis of the quasioptical waveguide resonator with mode selector is investigated experimentally. It is shown that the proposed method for the selection of transverse modes by an iris diaphragm on the plane mirror of a system of deflecting mirrors allows one to ensure the effective suppression of higher oscillation mode when operating of a laser in a wide spectral range. [ABSTRACT FROM AUTHOR]

It is demonstrated that localized states of an open quasi-one-dimensional quantum dot can be charged by the Coulomb blockade mechanism. A new effect—Coulomb oscillations of the ballistic conductance—is observed because of the high sensitivity of the ballistic current to single-electron variations of the self-consistent potential of the dot. The model proposed explains experimental results [C.-T. Liang, M. Y. Simmons, C. G. Smith, etal., Phys. Rev. Lett. 81,3507 (1998)]. © 2001 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]