Soliton dual comb in crystalline microresonators

We present a novel compact dual-comb source based on a monolithic optical crystalline MgF$_2$ multi-resonator stack. The coherent soliton combs generated in two microresonators of the stack with the repetition rate of 12.1 GHz and difference of 1.62 MHz provided after heterodyning a 300 MHz wide radio-frequency comb. Analogous system can be used for dual-comb spectroscopy, coherent LIDAR applications and massively parallel optical communications.Comment: 5 pages, 5 figure

Photon losses depending on polarization mixedness

We introduce a quantum channel describing photon losses depending on the degree of polarization mixedness. This can be regarded as a model of quantum channel with correlated errors between discrete and continuous degrees of freedom. We consider classical information over a continuous alphabet encoded on weak coherent states as well as classical information over a discrete alphabet encoded on single photons using dual rail representation. In both cases we study the one-shot capacity of the channel and its behaviour in terms of correlation between losses and polarization mixedness

Effects of Size Polydispersity on the Extinction Spectra of Colloidal Nanoparticle Aggregates

We investigate the effect of particle polydispersity on the optical extinction spectra of colloidal aggregates of spherical metallic (silver) nanoparticles, taking into account the realistic interparticle gaps caused by layers of stabilizing polymer adsorbed on the metal surface (adlayers). The spectra of computer-generated aggregates are computed using two different methods. The coupled-multipole method is used in the quasistatic approximation and the coupled-dipole method beyond the quasistatics. The latter approach is applicable if the interparticle gaps are sufficiently wide relative to the particle radii. Simulations are performed for two different particle size distribution functions (bimodal and Gaussian), varying the number of particles per aggregate, and different distribution functions of the interparticle gap width. The strong influence of the latter factor on the spectra is demonstrated and investigated in detail

Weak selection and stability of localized distributions in Ostwald ripening

We support and generalize a weak selection rule predicted recently for the self-similar asymptotics of the distribution function (DF) in the zero-volume-fraction limit of Ostwald ripening (OR). An asymptotic perturbation theory is developed that, when combined with an exact invariance property of the system, yields the selection rule, predicts a power-law convergence towards the selected self-similar DF and agrees well with our numerical simulations for the interface- and diffusion-controlled OR.Comment: 4 pages, 2 figures, submitted to PR

FAVOR (FAst Variability Optical Registration) -- A Two-telescope Complex for Detection and Investigation of Short Optical Transients

An astronomical complex intended to detect optical transients (OTs) in a wide field and follow them up with high time resolution investigation is described.Comment: 4 pages, 3 figures. To be published in "Il Nuovo Cimento", Proceedings of the 4th Rome Workshop on Gamma-Ray Bursts in the Afterglow Era, eds. L. Piro, L. Amati, S. Covino, B. Gendr

Anharmonicity, vibrational instability and Boson peak in glasses

We show that a {\em vibrational instability} of the spectrum of weakly interacting quasi-local harmonic modes creates the maximum in the inelastic scattering intensity in glasses, the Boson peak. The instability, limited by anharmonicity, causes a complete reconstruction of the vibrational density of states (DOS) below some frequency $\omega_c$, proportional to the strength of interaction. The DOS of the new {\em harmonic modes} is independent of the actual value of the anharmonicity. It is a universal function of frequency depending on a single parameter -- the Boson peak frequency, $\omega_b$ which is a function of interaction strength. The excess of the DOS over the Debye value is $\propto\omega^4$ at low frequencies and linear in $\omega$ in the interval $\omega_b \ll \omega \ll \omega_c$. Our results are in an excellent agreement with recent experimental studies.Comment: LaTeX, 8 pages, 6 figure

Precursor Compounds for Cu2ZnSe2 Structure

Chemical deposition from aqueous environments has significant perspective among existing methods of obtaining Cu 2 Se and ZnSe thin films. This method eliminates using complex expensive equipment, high-temperature heating, and deep vacuum. In this work, the calculation method for predicting the border conditions for the formation of individual metal chalcogenides phases was presented and widely tested on practice. Energy-dispersive analysis was used to investigate the elemental composition of the films. According to the results of thermoelectric power method, the layers had hole type conductivity

ПРОГНОЗУВАННЯ БАКТЕРІЙНИХ ІНФЕКЦІЙНИХ УСКЛАДНЕНЬ У ПАЦІЄНТІВ ПРИ ТРАНСПЛАНТАЦІЇ ГЕМОПОЕТИЧНИХ СТОВБУРОВИХ КЛІТИН

Results of original study of risk factors of bacterial infectious complications during haematopoietic stem cell transplantation are presented in this article. Authors have conducted a complex analysis of effectiveness of sepsis biomarkers (procalcitonin, presepsin, C-reactive protein) among haematopoietic stem cell transplant recipients.Представлено результати оригінального дослідження, присвяченого визначенню чинників ризику розвитку бактерійних інфекційних ускладнень при трансплантації гемопоетичних стовбурових клітин. Авторами виконаний комплексний аналіз ефективності застосування біологічних маркерів інфекцій кровоплину (прокальцитоніну, пресепсину, С-реактівного білка) у реципієнтів гемопоетичних стовбурових клітин

Anharmonic vs. relaxational sound damping in glasses: I. Brillouin scattering from densified silica

This series discusses the origin of sound damping and dispersion in glasses. In particular, we address the relative importance of anharmonicity versus thermally activated relaxation. In this first article, Brillouin-scattering measurements of permanently densified silica glass are presented. It is found that in this case the results are compatible with a model in which damping and dispersion are only produced by the anharmonic coupling of the sound waves with thermally excited modes. The thermal relaxation time and the unrelaxed velocity are estimated.Comment: 9 pages with 7 figures, added reference