Stability of spinning ring solitons of the cubic-quintic nonlinear Schrodinger equation

We investigate stability of (2+1)-dimensional ring solitons of the nonlinear Schrodinger equation with focusing cubic and defocusing quintic nonlinearities. Computing eigenvalues of the linearised equation, we show that rings with spin (topological charge) s=1 and s=2 are linearly stable, provided that they are very broad. The stability regions occupy, respectively, 9% and 8% of the corresponding existence regions. These results finally resolve a controversial stability issue for this class of models.Comment: 10 pages, 5 figures, accepted to Phys. Lett.

Progress toward the P\mathcal{P}, T\mathcal{T}-odd Faraday effect: Light absorption by atoms briefly interacting with a laser beam

We investigate the process of photon absorption by atoms or molecules shortly interacting with a laser beam in the dipole approximation. Assuming that the interaction time $\tau$ is much smaller than the lifetime of the corresponding excited state, we examine the absorption probability as a function of $\tau$. Besides, we incorporate Doppler broadening due to nonzero temperature of the atoms (molecules). It is demonstrated that in the case of a zero detuning and without Doppler broadening, the absorption probability is quadratic in $\tau$. Once Doppler broadening is taken into account or the laser beam is off from the resonant frequency, the absorption probability becomes linear in $\tau$. Our findings are expected to be important for experimental studies in optical cells or cavities where atoms or molecules traverse continuous laser beams. The experimental prospects of searching for the electric dipole moment (EDM) of the electron are discussed in detail

New records and combinations in Neotropical \u3ci\u3ePremnobius\u3c/i\u3e Eichhoff (Coleoptera: Curculionidae: Scolytinae: Ipini) with an illustrated key to New World species

Three Neotropical species are transferred to the genus Premnobius Eichhoff (Coleoptera: Curculionidae: Scolytinae: Ipini): Premnobius assiduus (Schedl, 1961, from Xyleborus), P. flechtmanni (Wood, 2007, from Acanthotomicus) and P. neoajunctus (Schedl, 1967, from Xyleborus). An illustrated key is presented for the native and introduced species of the genus known from the New World

New records and combinations in Neotropical \u3ci\u3ePremnobius\u3c/i\u3e Eichhoff (Coleoptera: Curculionidae: Scolytinae: Ipini) with an illustrated key to New World species

Three Neotropical species are transferred to the genus Premnobius Eichhoff (Coleoptera: Curculionidae: Scolytinae: Ipini): Premnobius assiduus (Schedl, 1961, from Xyleborus), P. flechtmanni (Wood, 2007, from Acanthotomicus) and P. neoajunctus (Schedl, 1967, from Xyleborus). An illustrated key is presented for the native and introduced species of the genus known from the New World

Simulation of the Pneumatic System of a Seed Drill with a Vertical Flow Direction

The purpose of the work is to reveal the influence of conical directing agents on the speed and trajectory of particles movement in the vertical pneumatic conduit of the sowing machine and to establish their rational parameters. With the help of numerical modeling the particle flight trajectories in the air flow were obtained. The carried out researches have shown expediency of application of the conical directing agent, allowing to take away a longitudinal stream of particles from walls of a pneumatic conduit and to centre their trajectories of movement along an axis of a pneumatic conduit. Particles are focused to the center of the distributor when the distributor covers the area of pneumatic conduit cross-section close to 25%

, -Odd Effects in the LuOH⁺ Cation

The LuOH+ cation is a promising system to search for manifestations of time reversal and spatial parity violation effects. Such effects in LuOH+ induced by the electron electric dipole moment eEDM and the scalar-pseudoscalar interaction of the nucleus with electrons, characterized by ks constant, in LuOH+ are studied. The enhancement factors, polarization in the external electric field, hyperfine interaction, and rovibrational structure are calculated. The study is required for the experiment preparation and extraction of the eEDM and ks values from experimental data

T,P\mathcal{T,P}-odd effects in the LuOH+^+ cation

The LuOH$^+$ cation is a promising system to search for manifestations of time reversal and spatial parity violation effects. Such effects in LuOH$^+$ induced by the electron electric dipole moment $e$EDM and the scalar-pseudoscalar interaction of the nucleus with electrons, characterized by $k_s$ constant, in LuOH$^+$ are studied. The enhancement factors, polarization in the external electric field, hyperfine interaction, rovibrational structure are calculated. The study is required for the experiment preparation and extraction of the eEDM and ks values from experimental data

Optomechanical manipulation with hyperbolic metasurfaces

Auxiliary nanostructures introduce additional flexibility into optomechanical manipulation schemes. Metamaterials and metasurfaces capable to control electromagnetic interactions at the near-field regions are especially beneficial for achieving improved spatial localization of particles, reducing laser powers required for trapping, and for tailoring directivity of optical forces. Here, optical forces acting on small particles situated next to anisotropic substrates, are investigated. A special class of hyperbolic metasurfaces is considered in details and is shown to be beneficial for achieving strong optical pulling forces in a broad spectral range. Spectral decomposition of the Green functions enables identifying contributions of different interaction channels and underlines the importance of the hyperbolic dispersion regime, which plays the key role in optomechanical interactions. Homogenised model of the hyperbolic metasurface is compared to its metal-dielectric multilayer realizations and is shown to predict the optomechanical behaviour under certain conditions related to composition of the top layer of the structure and its periodicity. Optomechanical metasurfaces open a venue for future fundamental investigations and a range of practical applications, where accurate control over mechanical motion of small objects is required

Macroscopic model of formation of the domain of multiple filamentation in glass and water

The results of natural experiments of the propagation of powerful femtosecond laser radiation in glass and water