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Vibrational resonance in the FitzHugh-Nagumo neuron model under state-dependent time delay

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arXiv 2024年

作者： Siewe, M. Siewe Rajasekar, S. Coccolo, Mattia Sanjuán, Miguel A.F. University of Yaounde I Faculty of Science Department of Physics Laboratory of Mechanics Materials and Structures PO. Box: Yaounde812 Cameroon School of Physics Bharathidasan University Tamilnadu Tiruchirapalli620024 India Nonlinear Dynamics Chaos and Complex Systems Group Departamento de Física Universidad Rey Juan Carlos Tulipán s/n Móstoles Madrid28933 Spain

We propose a nonlinear FitzHugh–Nagumo neuronal model with an asymmetric potential driven by both a high-frequency and a low-frequency signal. Our numerical analysis focuses on the influence of a state-dependent time delay on vibrational resonance and delay-induced resonance phenomena. The response amplitude at the low-frequency is explored to characterize the vibrational resonance and delay-induced resonance. Our results show that for smaller values of the amplitude of the state-dependent time-delay velocity component, vibrational resonance and multi-resonance occur in the neuronal model. For large values of the high-frequency excitation amplitude, vibrational resonance appears with one peak. Furthermore, we observe a change in the response when the amplitude of the state-dependent time-delay velocity component increases. In addition, we analyze how the state-dependent time-delay position and velocity components can give birth to delay-induced resonance for separate and together. The key findings of this work demonstrate that the state-dependent time-delay velocity component plays a crucial role in both phenomena. Specifically, the delay parameter serves as a critical control factor, capable of triggering the onset of the two *** Codes 65 © 2024, CC BY.

关键词： Time delay

Influence of strong electric field on the polaron properties in semiconductor quantum dot

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Research Square

Research Square 2023年

作者： Noupeyi, S.D. Nguepnang, J.V. Ekengoue, C.M. Kenfack-Jiotsa, A. Laboratory of Mechanics Materials and Structure Faculty of Sciences University of Yaounde I Yaounde Cameroon Nonlinear Physics and Complex Systems Group The Higher Teacher’s Training College University of Yaounde I Yaounde Cameroon University of Buea South-West Cameroon Cameroon Dschang Cameroon

Polarons are quasiparticles that result from a strong coupling regime between electron or a hole and ions in nanomaterials. Polarons manifest themselves in many different ways under the influence of external electric and (or) magnetic fields. This paper investigates the influence of strong electric field on polaron properties in semiconductor quantum dot (SCQD). We used the modified Lee Low Pines Huybrecht method to derive fundamental and first state energy of polaron. The superposition of these two states energies which form a quantum bit considered as a two level system (TLS) allowed us to evaluate the probability density, capacitance and conductance of the polaron under the Drude model. Our results indicate that the electric field possesses pronounced effects on the properties of polaron in SCQD. Some of these effects include but are not limited to: (i) the variation of the probability density according to the x and y planar coordinates;(2i) the periodical modification of the probability density with electric field frequency and its dependence on longitudinal optical (LO) phonon-coupling strength constant;(3i) the observation of both positive and negative values of the energy of the system, indicating the formation of free and couple polaronic entities in the system. In particular, we found that the ground state energy of the polaron is predominant in Galium Arsenide (GaAs) SCQD. It comes that, the investigation of strong polaron-electric field (laser radiation) is quite indicated in the case of Galium Arsenide (GaAs). © 2023, CC BY.

关键词： Semiconductor quantum dots

Role of higher-order interactions on the modulational instability of Bose-Einstein condensate trapped in a periodic optical lattice

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arXiv 2022年

作者： Subramaniyan, Sabari Lekeufack, O.T. Yamgoue, S.B. Tamilthiruvalluvar, R. Radha, R. Institute of Theoretical Physics UNESP Universidade Estadual Paulista SP São Paulo01156-970 Brazil Pure physics Laboratory Group of nonlinear physics and complex systems Department of Physics Faculty of Science University of Douala P.O. Box 24157 Douala Cameroon Université de Yaoundé I Yaoundé Cameroon Department of Physics University of Bamenda P.O Box 39 Bamenda Cameroon Cameroon Kumbakonam612001 India

In this paper, we investigate the impact of higher-order interactions on the modulational instability (MI) of Bose-Einstein Condensates (BECs) immersed in an optical lattice potential. We derive the new variational equations for the time evolution of amplitude, phase of modulational perturbation, and effective potential for the system. Through effective potential techniques, we find that high density attractive and repulsive BECs exhibit new character with direct impact over the MI phenomenon. Results of intensive numerical investigations are presented and their convergence with the above semi analytical approach is brought out. © 2022, CC BY.

关键词： Optical lattices

Vibrational resonance: A review

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arXiv 2024年

作者： Yang, Jianhua Rajasekar, S. Sanjuán, Miguel A.F. Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment School of Mechatronic Engineering China University of Mining and Technology Jiangsu Xuzhou221116 China School of Physics Bharathidasan University Tamilnadu Tiruchirapalli620024 India Nonlinear Dynamics Chaos and Complex Systems Group Departamento de Fisica Universidad Rey Juan Carlos Tulipan s/n Mostoles Madrid28933 Spain

Over the past two decades, vibrational resonance has garnered significant interest and evolved into a prominent research field. Classical vibrational resonance examines the response of a nonlinear system excited by two signals: a weak, slowly varying characteristic signal, and a fast-varying auxiliary signal. The characteristic signal operates on a much longer time scale than the auxiliary signal. Through the cooperation of the nonlinear system and these two excitations, the faint input can be substantially amplified, showcasing the constructive role of the fast-varying signal. Since its inception, vibrational resonance has been extensively studied across various disciplines, including physics, mathematics, biology, neuroscience, laser science, chemistry, and engineering. Here, we delve into a detailed discussion of vibrational resonance and the most recent advances, beginning with an introduction to characteristic signals commonly used in its study. Furthermore, we compile numerous nonlinear models where vibrational resonance has been observed to enhance readers’ understanding and provide a basis for comparison. Subsequently, we present the metrics used to quantify vibrational resonance, as well as offer a theoretical formulation. This encompasses the method of direct separation of motions, linear and nonlinear vibrational resonance, re-scaled vibrational resonance, ultrasensitive vibrational resonance, and the role of noise in vibrational resonance. Later, we showcase two practical applications of vibrational resonance: one in image processing and the other in fault diagnosis. This presentation offers a comprehensive and versatile overview of vibrational resonance, exploring various facets and highlighting promising avenues for future research in both theory and engineering applications. © 2024, CC BY.

关键词： nonlinear systems

Continuous signaling pathways instability in an electromechanical coupled model for biomembranes and nerves

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The European Physical Journal B 2022年第1期95卷 1-22页

作者： Kamga, A. S. Foualeng Achu, G. Fongang Kakmeni, F. M. Moukam Ghomsi, P. Guemkam Ndjomatchoua, Frank T. Tchawoua, Clément Laboratory of Mechanics Materials and Structures Research and Postgraduate Training Unit for Physics and Applications Postgraduate School of Science Technology and Geosciences Department of Physics Faculty of Science University of Yaoundé 1 Ngoa Ekelle Cameroon Complex Systems and Theoretical Biology Group Laboratory of Research on Advanced Materials and Nonlinear Science (LaRAMaNS) Department of Physics Faculty of Science University of Buea Buea Cameroon Sustainable Impact Platform Adaptive Agronomy and Pest Ecology Cluster International Rice Research Institute (IRRI) Metro Manila Philippines

Information processing is a basic part of life and, presumably, the nervous system’s primary purpose. Neurons perform a variety of tasks that collect useful information from the organism’s periphery sensor receptor arrays and transfer it into action, imagery, and memory. Brain communication, also known as neural signaling, is now assumed to be electromechanical, based on a large body of observational and experimental evidence acquired over the last two centuries. In this paper, modulational instability is investigated as a mechanism of wave trains and soliton formation in neurons using a nonlinearly coupled complex Ginzburg–Landau equation derived from the Morris–Lecar neural model for nerve electrical activity and the Heimburg–Jackson model for longitudinal density pulses. Using standard linear stability analysis, the growth rate of modulation instability is studied analytically and numerically as a function of perturbation frequency and system parameters. In particular, it is shown that the gain depends strongly on the coupling parameters. We also investigated the effect of coupling parameters on the gain of modulation instability, thus confirming the continuous signaling instability. This is highly significant from a theoretical point of view and could be a plus to explain the process of generation of action potential as the consequences of instability between coupled electrical and mechanical weakly continuous wave in nerve.

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Controlling second-order rogue matter wave and line bright soliton dynamics in 2D Bose-Einstein Condensate with higher-order interactions and gain/loss atoms

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arXiv 2025年

作者： Nkenfack, Cyrille Edgard Lekeufack, Olivier Tiokeng Sabari, Subramaniyan Yamapi, Rene Kofane, Timoleon Crepin Pure physics Laboratory Group of nonlinear physics and complex systems Department of Physics Faculty of Science University of Douala P.O. Box 24157 Douala Cameroon SP São Paulo01140-070 Brazil Department of Physics and Astronomy Botswana International University of Science and Technology Private Mail Bag 16 Palapye Botswana

We investigate the two-dimensional modified Gross-Pitaevskii equation, accounting for the effects of atom gain/loss and a time-independent isotropic confining potential, utilizing the Hirota’s bilinear method. Through an appropriate bilinear form, we derive exact one-soliton and multi-soliton solutions. These solutions showcase two prominent phenomena: the second-order rogue matter wave with spatio-temporal localization, and the line soliton with double spatial localization. We demonstrate the feasibility of controlling the soliton amplitude and the effects of gain/loss resulting in areas of collapse by suitably tuning the coefficient of higher-order interactions in the Bose-Einstein condensate. Additionally, by exploring the interaction dynamics of the multi-soliton solutions, we identify elastic-type interactions, claiming the intrinsic properties of solitons. The influence of higher-order interactions and gain/loss terms on the interaction dynamics is also thoroughly analyzed. These analyses demonstrate that, within the framework of Bose-Einstein condensates described by the two-dimensional modified Gross-Pitaevskii equation, higher-order interactions provide a means to control the properties of the generated rogue matter waves. Intensive numerical simulations are performed and their convergence with theoretical predicted results then throw light about the emergent features of the chosen solutions. The exact analytical solutions derived in this study rigorously satisfy the original equation, which ensures their consistency with the numerical results and confirms their accuracy. Thus, our findings hold promise for potential future applications. © 2025, CC BY.

关键词： Solitons

Annealing approach to root-finding

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arXiv 2024年

作者： Jo, Junghyo Wagemakers, Alexandre Periwal, Vipul Department of Physics Education Seoul National University Seoul08826 Korea Republic of Center for Theoretical Physics and Artificial Intelligence Institute Seoul National University Seoul08826 Korea Republic of School of Computational Sciences Korea Institute for Advanced Study Seoul02455 Korea Republic of Nonlinear Dynamics Chaos and Complex Systems Group Departamento de Física Universidad Rey Juan Carlos Tulipán s/n Móstoles Madrid28933 Spain Laboratory of Biological Modeling National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health BethesdaMD20892 United States

The Newton-Raphson method is a fundamental root-finding technique with numerous applications in physics. In this study, we propose a parameterized variant of the Newton-Raphson method, inspired by principles from physics. Through analytical and empirical validation, we demonstrate that this novel approach offers increased robustness and faster convergence during root-finding iterations. Furthermore, we establish connections to the Adomian series method and provide a natural interpretation within a series framework. Remarkably, the introduced parameter, akin to a temperature variable, enables an annealing approach. This advancement sets the stage for a fresh exploration of numerical iterative root-finding methodologies. Copyright © 2024, The Authors. All rights reserved.

关键词： Newton-Raphson method

Dynamics of Cubic-Quintic nonlinear Pt-Symmetry Mechanical Oscillators

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SSRN

SSRN 2022年

作者： Azeghap-Simo, Ibrahim Fotsa-Ngaffo, Fernande Kenfack-Jiotsa, Aurélien Laboratory of Mechanics Materials and Structures Department of Physics Faculty of Science University of Yaound I P.O. Box 812 Yaoundé Cameroon Nonlinear and Complex Systems Physics Group Departement of Physics The Higher Teacher Training College University of Yaounde I P.O. Box 47 Yaoundé Cameroon Institute of Wood Technologies University of Yaoundé I P.O. Box 306 Mbalmayo Cameroon Department of Physics Higher Teacher Training College University of Yaound I P.O. Box 47 Yaoundé Cameroon

In this paper, we investigate the dynamic of two mechanical coupled oscillators (MCO) with Parity-Time (PT) Symmetry i.e., one has gain and the other has an equal and opposite amount of loss, in linear limit and with the hard/soft Duffing cubic or quintic nonlinearities. In the linear regime, we find the eigenvalues and determine the PT-symmetry breaking threshold point (BTP). In the nonlinear level, the Hamilton function is derived and the stability of the different branches of fixed points (FP) found is analyzed. The numerical treatment shows that the stability of the system depends on the nonlinearity and the initial conditions. The analytical approach reveals that the stability is governed by the eigenfrequencies of the system. Correspondences are found between the numerical and the analytical results. © 2022, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

Non-Hermitian Electronics Multipods of Electromagnetically Induced Transparency (EIT) and Absorption (EIA)

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Research Square

Research Square 2021年

作者： Tagouegni, Senghor Fotsa-Ngaffo, Fernande Kenfack-Jiotsa, Aurélien Laboratory of Mechanics Materials and Structures Department of Physics Faculty of Science University of Yaoundé I P.O. Box 812 Yaoundé Cameroon Nonlinear Physics and Complex Systems Group Department of Physics Higher Teacher’s Training College University of Yaoundé I P.O. Box 47 Yaoundé Cameroon Institute of Wood technologies University of Yaoundé I P.O. Box 306 Mbalmayo Cameroon

We study a non-Hermitian electronic dimers system based on an imaginary resistor (Z) in a (N+2) level atomic multi-pod configuration. Non-Hermitian systems depend on a gain/loss parameter and are specifically marked by a degeneracy exhibited at an exceptional point (EP) separating different phases of complex modes dynamics. Interestingly, the structural characterization and the dispersive properties reveal a broad range of strong coupling where the interplay between the control and the probe field induce a simultaneous EIT, EIA and ATS. Here, by identifying the underlying physical mechanisms, we show that multiple windows of transparency can be strongly enhanced by the incorporation of several dimers in the multipod network. On the other hand, if the pumping field is resonant in the weak regime, multiple EIT and EIA windows result in the number of dimers. Remarkably, the proposed system embedded a multiple coupling mechanism whose modulation induces a couplingless point whereby the energy cross. At this point EIT and related phenomena vanish. © 2021, CC BY.

关键词： Quantum optics