36 research outputs found
Two-color nonlinear localized photonic modes
We analyze second-harmonic generation (SHG) at a thin effectively quadratic
nonlinear interface between two linear optical media. We predict multistability
of SHG for both plane and localized waves, and also describe two-color
localized photonic modes composed of a fundamental wave and its second harmonic
coupled together by parametric interaction at the interface.Comment: 4 pages, 5 figures (updated references
Instabilities and Bifurcations of Nonlinear Impurity Modes
We study the structure and stability of nonlinear impurity modes in the
discrete nonlinear Schr{\"o}dinger equation with a single on-site nonlinear
impurity emphasizing the effects of interplay between discreteness,
nonlinearity and disorder. We show how the interaction of a nonlinear localized
mode (a discrete soliton or discrete breather) with a repulsive impurity
generates a family of stationary states near the impurity site, as well as
examine both theoretical and numerical criteria for the transition between
different localized states via a cascade of bifurcations.Comment: 8 pages, 8 figures, Phys. Rev. E in pres
Electron-electron scattering effects on the Full Counting Statistics of Mesoscopic Conductors
In the hot electron regime, electron-electron scattering strongly modifies
not only the shot noise but also the full counting statistics. We employ a
method based on a stochastic path integral to calculate the counting statistics
of two systems in which noise in the hot electron regime has been
experimentally measured. We give an analytical expression for the counting
statistics of a chaotic cavity and find that heating due to electron-electron
scattering renders the distribution of transmitted charge symmetric in the shot
noise limit. We also discuss the frequency dispersion of the third order
correlation function and present numerical calculations for the statistics of
diffusive wires in the hot electron regime
Perturbation-induced radiation by the Ablowitz-Ladik soliton
An efficient formalism is elaborated to analytically describe dynamics of the
Ablowitz-Ladik soliton in the presence of perturbations. This formalism is
based on using the Riemann-Hilbert problem and provides the means of
calculating evolution of the discrete soliton parameters, as well as shape
distortion and perturbation-induced radiation effects. As an example, soliton
characteristics are calculated for linear damping and quintic perturbations.Comment: 13 pages, 4 figures, Phys. Rev. E (in press
Current noise in long diffusive SNS junctions in the incoherent MAR regime
Spectral density of current fluctuations at zero frequency is calculated for
a long diffusive SNS junction with low-resistive interfaces. At low
temperature, T << Delta, the subgap shot noise approaches linear voltage
dependence, S=(2/ 3R)(eV + 2Delta), which is the sum of the shot noise of the
normal conductor and voltage independent excess noise. This result can also be
interpreted as the 1/3-suppressed Poisson noise for the effective charge q =
e(1+2Delta/eV) transferred by incoherent multiple Andreev reflections (MAR). At
higher temperatures, anomalies of the current noise develop at the gap
subharmonics, eV = 2Delta/n. The crossover to the hot electron regime from the
MAR regime is analyzed in the limit of small applied voltages.Comment: improved version, to be published in Phys. Rev.
Engineered nonlinear lattices
We show that with the quasi-phase-matching technique it is possible to fabricate stripes of nonlinearity that trap and guide light like waveguides. We investigate an array of such stripes and find that when the stripes are sufficiently narrow, the beam dynamics is governed by a quadratic nonlinear discrete equation. The proposed structure therefore provides an experimental setting for exploring discrete effects in a controlled manner. In particular, we show propagation of breathers that are eventually trapped by discreteness. When the stripes are wide the beams evolve in a structure we term a quasilattice, which interpolates between a lattice system and a continuous system.Peer ReviewedPostprint (published version
The pebble fines contribution into radiation environment of the river Yenisei floodplain in an influence zone of the Krasnoyarsk mining and chemical combine (KMCC)
The results of investigation of radioactive contamination of the river Yenisei bed pebbles in an influence zone of the KMCC (especially in its near-field part) are presented in this work. It is demonstrated, that pebbles can contain up to 30 % of the total amount of γ-emitting technogenic radionuclides (TRN) in the places with overlying soils. In addition, river bed pebbles, situated in permanently washing riverside sections of islands and banks, can contain significant amount of TRN too. These facts considerably increase an estimation of TRN reserves in the Yenisei floodplain. Without the contribution of the river bed pebbles the fraction of TRN, accumulated in the underlying and tow path pebbles in the near and far-field influence zones of the KMCC, can reach 7,9% for 137Cs, 5,8% for 152Eu, 5,6% for 154Eu and <3% for 60Co of their total amount
Analysis of magnetorefractive effect in La₀.₇Ca₀.₃MnO₃ thin films in the IR spectral range
We have reported the results of investigation of a magneto refractive effect on magnetoreflection and magnetotransmission modes in La₀.₇Ca₀.₃MnO₃ manganite thin films and crystals in the middle IR spectral range. The effects can reach several percents for single crystals and up to 20—40 % for thin films near Curie temperature. It was shown that the magnitude and spectra of the magnetorefractive effect strongly depend on magnetoresistance and optical properties of manganites. The overall qualitative agreement was obtained between the calculated in the framework of the effective medium approach data and experimental data
Static and time-resolved mid-infrared spectroscopy of Hg0.95Cd0.05Cr2Se4 spinel
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