arXiv subjects

Oskar A. Sultanov

Publications and source records attributed to Oskar A. Sultanov.

9 recordsLinked to original sources

arXiv2026

Resonance in coupled nonlinear oscillators with decaying perturbations

The influence of nonautonomous perturbations on a system of two coupled nonlinear non-identical oscillators is studied. Both the coupling intensity and the perturbation strength are assumed to decay in time according to a power law. We focus on resonance effects associated with the commensurability of the natural frequencies of the oscillators at some energy levels. In particular, we describe the conditions on perturbations and coupling parameters under which phase-locked solutions appear with the oscillator energies remaining asymptotically close to resonant levels. By combining the averaging method with the construction of Lyapunov functions, we derive a nonautonomous model system governing the perturbed dynamics and analyse the stability of resonant solutions in the phase-locking regime. The theoretical results are illustrated for a system of non-identical Duffing oscillators with decaying coupling.

math.DS↗

arXiv2025

Resonance in isochronous systems with decaying oscillatory and stochastic perturbations

The combined influence of oscillatory excitations and multiplicative stochastic perturbations of white noise type on isochronous systems in the plane is investigated. It is assumed that the intensity of perturbations decays with time and the excitation frequency satisfies a resonance condition. The occurrence and stochastic stability of solutions with an asymptotically constant amplitude are discussed. By constructing an averaging transformation, we derive a model truncated deterministic system that describes possible asymptotic regimes for perturbed solutions. The persistence of resonant solutions in the phase locking and the phase drifting modes is justified by constructing suitable Lyapunov functions for the complete stochastic system. In particular, we show that decaying stochastic perturbations can shift the boundary of stability domain for resonant solutions.

math.DS↗

arXiv2025

Nonlinear resonance in systems with decaying perturbations and noise

The effect of multiplicative white noise on the resonance capture in non-isochronous systems with time-decaying pumping is investigated. It is assumed that the intensity of perturbations decays with time, and its frequency is asymptotically constant. The occurrence of attractive solutions with an amplitude close to the resonant value and a phase synchronized with the excitation are considered. The persistence of such a regime in a stochastically perturbed system is analyzed. By combining the averaging method and the construction of suitable stochastic Lyapunov functions, conditions are derived that guarantee the stochastic stability of the resonant modes on infinite or asymptotically large time intervals. The proposed theory is applied to the Duffing oscillator with decaying parametric excitation and noise.

math.DS↗

arXiv2024

Resonance in isochronous systems with decaying oscillatory perturbations

Non-autonomous perturbations of isochronous systems in the plane are considered. It is assumed that the intensity of perturbations decays with time, and the frequency is asymptotically constant with the limiting value satisfying a resonance condition. We discuss the emergence of attracting resonant solutions with an asymptotically constant amplitude. By combining the averaging technique and the Lyapunov function method, we show that this behaviour can occur in the phase locking and phase drifting regimes. The conditions that guarantee the existence and stability of such resonant dynamics are described.

math.DS↗

arXiv2024

Resonances in nonlinear systems with a decaying chirped-frequency excitation and noise

The influence of multiplicative white noise on the resonance capture of strongly nonlinear oscillatory systems under chirped-frequency excitations is investigated. It is assumed that the intensity of the perturbation decays polynomially with time, and its frequency grows according to a power low. Resonant solutions with a growing amplitude and phase, synchronized with the excitation, are considered. The persistence of such a regime in the presence of stochastic perturbations is discussed. In particular, conditions are described that guarantee the stochastic stability of the resonant modes on infinite or asymptotically large time intervals. The technique used is based on a combination of the averaging method, stability analysis and construction of stochastic Lyapunov functions. The proposed theory is applied to the Duffing oscillator with a chirped-frequency excitation and noise.

math.DS↗

arXiv2023

Nonlinear resonance in oscillatory systems with decaying perturbations

Time-decaying perturbations of nonlinear oscillatory systems in the plane are considered. It is assumed that the unperturbed systems are non-isochronous and the perturbations oscillate with an asymptotically constant frequency. Resonance effects and long-term asymptotic regimes for solutions are investigated. In particular, the emergence of stable states close to periodic ones is discussed. By combining the averaging technique and stability analysis, the conditions on perturbations are described that guarantee the existence and stability of the phase-locking regime with a resonant amplitude. The results obtained are applied to the perturbed Duffing oscillator.

math.DS↗

arXiv2023

Stability of asymptotically Hamiltonian systems with damped oscillatory and stochastic perturbations

A class of asymptotically autonomous systems on the plane with oscillatory coefficients is considered. It is assumed that the limiting system is Hamiltonian with a stable equilibrium. The effect of damped multiplicative stochastic perturbations of white noise type on the stability of the system is discussed. It is shown that different long-term asymptotic regimes for solutions are admissible in the system and the stochastic stability of the equilibrium depends on the realized regime. In particular, we show that stable phase locking is possible in the system due to decaying stochastic perturbations. The proposed analysis is based on a combination of the averaging technique and the construction of stochastic Lyapunov functions.

math.DS↗

arXiv2023

Asymptotic regimes in oscillatory systems with damped non-resonant perturbations

An autonomous system of ordinary differential equations describing nonlinear oscillations on the plane is considered. The influence of time-dependent perturbations decaying at infinity in time is investigated. It is assumed that the perturbations satisfy the non-resonance condition and do not vanish at the equilibrium of the limiting system. Possible long-term asymptotic regimes for perturbed solutions are described. In particular, we show that the perturbed system can behave like the corresponding limiting system or new asymptotically stable regimes may appear. The proposed analysis is based on the combination of the averaging technique and the construction of Lyapunov functions.

math.DS↗

arXiv2020

Stability and bifurcation phenomena in asymptotically Hamiltonian systems

The influence of time-dependent perturbations on an autonomous Hamiltonian system with an equilibrium of center type is considered. It is assumed that the perturbations decay at infinity in time and vanish at the equilibrium of the unperturbed system. In this case the stability and the long-term behaviour of trajectories depend on nonlinear and non-autonomous terms of the equations. The paper investigates bifurcations associated with a change of Lyapunov stability of the equilibrium and the emergence of new attracting or repelling states in the perturbed asymptotically autonomous system. The dependence of bifurcations on the structure of decaying perturbations is discussed.

math.DS↗