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E. V. Zemlyanaya

Publications and source records attributed to E. V. Zemlyanaya.

43 records · Page 3Linked to original sources
arXiv2003

Testing $^{6,8}$He density distributions by calculations of total reaction cross-sections of $^{6,8}$He+$^{28}$Si

Calculations of the $^{6,8}$He + $^{28}$Si total reaction cross sections at intermediate energies are performed on the basis of the Glauber-Sitenko microscopic optical-limit model. The target-nucleus density distribution is taken from the electron-nucleus scattering data, and the $^{6,8}$He densities are used as they are derived in different models. The results of the calculations are compared with the existing experimental data. The effects of the density tails of the projectile nuclei as well as the role of shell admixtures and short-range correlations are analyzed.

nucl-th↗
arXiv2003

Traveling solitons in the damped driven nonlinear Schrödinger equation

The well known effect of the linear damping on the moving nonlinear Schrödinger soliton (even when there is a supply of energy via the spatially homogeneous driving) is to quench its momentum to zero. Surprisingly, the zero momentum does not necessarily mean zero velocity. We show that two or more parametrically driven damped solitons can form a complex traveling with zero momentum at a nonzero constant speed. All traveling complexes we have found so far, turned out to be unstable. Thus, the parametric driving is capable of sustaining the uniform motion of damped solitons, but some additional agent is required to stabilize it.

nlin.PS↗
arXiv2002

Parametrically Driven Dark Solitons

We show that unlike the bright solitons, the parametrically driven kinks are immune from instabilities for all dampings and forcing amplitudes; they can also form stable bound states. In the undamped case, the two types of stable kinks and their complexes can travel with nonzero velocities.

nlin.PS↗
arXiv2001

Two and three-dimensional oscillons in nonlinear Faraday resonance

We study 2D and 3D localised oscillating patterns in a simple model system exhibiting nonlinear Faraday resonance. The corresponding amplitude equation is shown to have exact soliton solutions which are found to be always unstable in 3D. On the contrary, the 2D solitons are shown to be stable in a certain parameter range; hence the damping and parametric driving are capable of suppressing the nonlinear blowup and dispersive decay of solitons in two dimensions. The negative feedback loop occurs via the enslaving of the soliton's phase, coupled to the driver, to its amplitude and width.

nlin.PS↗
arXiv1999

Existence threshold for the ac-driven damped nonlinear Schrödinger solitons

It has been known for some time that solitons of the externally driven, damped nonlinear Schrödinger equation can only exist if the driver's strength, $h$, exceeds approximately $(2/ π) γ$, where $γ$ is the dissipation coefficient. Although this perturbative result was expected to be correct only to the leading order in $γ$, recent studies have demonstrated that the formula $h_{thr}= (2 /π) γ$ gives a remarkably accurate description of the soliton's existence threshold prompting suggestions that it is, in fact, exact. In this note we evaluate the next order in the expansion of $h_{thr}(γ)$ showing that the actual reason for this phenomenon is simply that the next-order coefficient is anomalously small: $h_{thr}=(2/ π) γ+ 0.002 γ^3$. Our approach is based on a singular perturbation expansion of the soliton near the turning point; it allows to evaluate $h_{thr}(γ)$ to all orders in $γ$ and can be easily reformulated for other perturbed soliton equations.

patt-sol↗
arXiv1996

Emission of Two Hard Photons in Large-Angle Bhabha Scattering

A closed expression for the differential cross section of the large-angle Bhabha $e^+ e^-$ scattering which explicitly takes into account the leading and next-to-leading contributions due to the emission of two hard photons is presented. Both collinear and semi-collinear kinematical regions are considered. The results are illustrated by numerical calculations.

hep-ph↗