Two-dimensional Nonlinear Map Research Articles

Dissipative fractional standard maps: Riemann-Liouville and Caputo.

In this study, given the inherent nature of dissipation in realistic dynamical systems, we explore the effects of dissipation within the context of fractional dynamics. Specifically, we consider the dissipative versions of two well known fractional maps: the Riemann-Liouville (RL) and the Caputo (C) fractional standard maps (fSMs). Both fSMs are two-dimensional nonlinear maps with memory given in action-angle variables (In,θn), with n being the discrete iteration time of the maps. In the dissipative versions, these fSMs are parameterized by the strength of nonlinearity K, the fractional order of the derivative α∈(1,2], and the dissipation strength γ∈(0,1]. In this work, we focus on the average action ⟨In⟩ and the average squared action ⟨In2⟩ when K≫1, i.e., along strongly chaotic orbits. We first demonstrate, for |I0|>K, that dissipation produces the exponential decay of the average action ⟨In⟩≈I0exp⁡(-γn) in both dissipative fSMs. Then, we show that while ⟨In2⟩RL-fSM barely depends on α (effects are visible only when α→1), any α<2 strongly influences the behavior of ⟨In2⟩C-fSM. We also derive an analytical expression able to describe ⟨In2⟩RL-fSM(K,α,γ).

Tunable subdiffusion in the Caputo fractional standard map

The Caputo fractional standard map (C-fSM) is a two-dimensional nonlinear map with memory given in action–angle variables (I,θ). It is parameterized by K and α∈(1,2] which control the strength of nonlinearity and the fractional order of the Caputo derivative, respectively. In this work we perform a scaling study of the average squared action I2 along strongly chaotic orbits, i.e. when K≫1. We numerically prove that I2∝nμ with 0≤μ(α)≤1, for large enough discrete times n. That is, we demonstrate that the C-fSM displays subdiffusion for 1<α<2. Specifically, we show that diffusion is suppressed for α→1 since μ(1)=0, while standard diffusion is recovered for α=2 where μ(2)=1. We describe our numerical results with a phenomenological analytical estimation.

Scaling properties of the action in the Riemann-Liouville fractional standard map.

The Riemann-Liouville fractional standard map (RL-fSM) is a two-dimensional nonlinear map with memory given in action-angle variables (I,θ). The RL-fSM is parameterized by K and α∈(1,2], which control the strength of nonlinearity and the fractional order of the Riemann-Liouville derivative, respectively. In this work we present a scaling study of the average squared action 〈I^{2}〉 of the RL-fSM along strongly chaotic orbits, i.e., for K≫1. We observe two scenarios depending on the initial action I_{0}, I_{0}≪K or I_{0}≫K. However, we can show that 〈I^{2}〉/I_{0}^{2} is a universal function of the scaled discrete time nK^{2}/I_{0}^{2} (n being the nth iteration of the RL-fSM). In addition, we note that 〈I^{2}〉 is independent of α for K≫1. Analytical estimations support our numerical results.

Multiple Reflections for Classical Particles Moving under the Influence of a Time-Dependent Potential Well

We study the dynamics of classical particles confined in a time-dependent potential well. The dynamics of each particle is described by a two-dimensional nonlinear discrete mapping for the variables energy and phase of the periodic moving well. We obtain the phase space and show that it contains periodic islands, chaotic sea, and invariant spanning curves. We find the elliptic and hyperbolic fixed points and discuss a numerical method to obtain them. We study the dispersion of the initial conditions after a single iteration. This study allows finding regions where multiple reflections occur. Multiple reflections happen when a particle does not have enough energy to exit the potential well and is trapped inside it, suffering several reflections until it has enough energy to exit. We also show deformations in regions with multiple reflection, but the area remains constant when we change the control parameter . Finally, we show some structures that appear in the plane by using density plots.

Nonlinear elite generation change model

The purpose of the presented article was to build a concise conceptual mathematical model of the competitive dynamics of alternative types of social activity. The model was developed in the form of a discrete two-dimensional non-linear mapping. The proposed mapping is new and has not been previously studied either in the field of mathematical social dynamics (sociophysics), or in the section of discrete models of nonlinear dynamics. The approach we used corresponds to the ideas of the theory of social time put forward by F. Braudel. Nonlinear two-dimensional mapping, in a paradoxical way, given the general socio-economic ideas about the relationship between generations, as it turned out, has a Hamiltonian structure. The analysis showed that both formally and in terms of qualitative behavior it is close to the standard model describing a rotator under the action of impacts. It was found that, depending not only on the parameters of the problem, but also on the initial conditions, in this case, periodic, quasiperiodic, and chaotic dynamics are simultaneously possible. Within the framework of the model, this means a great variety of intergenerational relationships. Thus, the data in the system will not be “forgotten”. The influence on the dynamics of the model of “dissipative additions” describing the degradation of the elite, the desire of society to “eliminate the best” is demonstrated. The dynamics of the system and its dependence on parameters become much simpler; nevertheless, cyclicity and multistability do not disappear in it. In this approximation, history turns out to be “local” — the details and peculiarities of society’s behavior will be “forgotten” after several generations. The study of the constructed model opens up great prospects for the analysis of various types of cyclical processes in mathematical history.

On Dynamic Investigations of Cournot Duopoly Game: When Firms Want to Maximize Their Relative Profits

This paper studies a Cournot duopoly game in which firms produce homogeneous goods and adopt a bounded rationality rule for updating productions. The firms are characterized by an isoelastic demand that is derived from a simple quadratic utility function with linear total costs. The two competing firms in this game seek the optimal quantities of their production by maximizing their relative profits. The model describing the game’s evolution is a two-dimensional nonlinear discrete map and has only one equilibrium point, which is a Nash point. The stability of this point is discussed and it is found that it loses its stability by two different ways, through flip and Neimark–Sacker bifurcations. Because of the asymmetric structure of the map due to different parameters, we show by means of global analysis and numerical simulation that the nonlinear, noninvertible map describing the game’s evolution can give rise to many important coexisting stable attractors (multistability). Analytically, some investigations are performed and prove the existence of areas known in literature with lobes.

A new cryptographic algorithm via a two-dimensional chaotic map

In this paper, a new cryptographic algorithm using a two-dimensional piecewise smooth nonlinear chaotic map is suggested. It depends on the confusion-diffusion model (permutation-substitution model). Firstly, the plain image is shuffled using the logistic map (confusion). Secondly, chaotic sequences are produced by two-dimensional piecewise smooth nonlinear chaotic map. Then, the produced sequences are preprocessed to integers between 0 and 255. Finally, the shuffled image is masked using the chaotic sequences (diffusion). The suggested algorithm is tested by different types of images. Furthermore, the decryption algorithm is implemented to retrieve the plain (original) image using the secret key. Experimental results and security analyses are applied using the suggested algorithm and its performances are validated with recent cryptographic algorithms. The security and performance analyses conclude that the suggested algorithm is secure, fast, and resists various attacks.

Multicritical behavior of the ferromagnetic Blume-Emery-Griffiths model with repulsive biquadratic couplings.

The ferromagnetic (J>0) version of the Blume-Emery-Griffiths model in the region of repulsive biquadratic couplings (K<0) is considered on a Cayley tree of coordination z, reducing the statistical problem to the analysis of a two-dimensional nonlinear discrete map. In order to investigate the effect of the coordination z on the system multicritical behavior, we study the particular case K/J=-3.5 with the inclusion of crystal fields (D≠0), but vanishing external magnetic fields (H=0), for two distinct lattice coordinations (z=4 and z=6). The thermodynamic solutions on the Bethe lattice (the central region of a large Cayley tree) are associated with the attractors of the two-dimensional map. The phase diagrams display several thermodynamic phases (paramagnetic, ferromagnetic, ferrimagnetic, and staggered quadrupolar). In some cases, there are regions of numerical costability of two different attractors of the map, associated with discontinuous phase transitions between the corresponding phases. To verify the thermodynamic stability of the phases and to locate the first-order boundaries, the analytical expression of the Gibbs free energy was obtained by the method proposed by Gujrati [Phys. Rev. Lett. 74, 809 (1995)PRLTAO0031-900710.1103/PhysRevLett.74.809]. For lower coordinations (z=4) the transition between the ferrimagnetic and the staggered quadrupolar phases is always continuous, while the transition between the ferromagnetic and the ferrimagnetic phases is discontinuous at low temperatures, turning into continuous for temperatures above a tricritical point. On the other hand, for higher coordinations (z=6), the transition between the ferromagnetic and the ferrimagnetic phases is always continuous. However, the transition between the ferrimagnetic and the staggered quadrupolar phases is continuous for higher temperatures and discontinuous for temperatures below a tricritical point, in agreement with previous results obtained in the mean-field approximation (infinity-coordination limit). In both cases, the occurrence and the thermodynamic stability of the ferrimagnetic phase is confirmed.

Nonlinear dynamics of charged particle slipping on rough surface with periodic force

This paper deals with two types of period-doubling bifurcation phenomena in a particle system, where the charged particle slips on rough surface with periodic force. The charged particle system is characterized by a two-dimensional nonlinear mapping, i.e., the Fermi–Ulam model (FUM) with dissipation. Based on the dissipative FUM, theoretical investigations are performed to identify the two types of period-doubling bifurcations with the assist of eigenvalue analysis approach and further to reveal their underlying mechanisms of the particle system as the strength of the periodic force for the particle system increases. Finally, bifurcation diagram and the maximum Lyapunov exponent are employed to analyze the dynamical evolution of bifurcation behaviors in the particle system quantitatively. These results are helpful for the in-depth understanding of transport mechanism of charged particle system.

Analytical description of critical dynamics for two-dimensional dissipative nonlinear maps

The critical dynamics near the transition from unlimited to limited action diffusion for two families of well known dissipative nonlinear maps, namely the dissipative standard and dissipative discontinuous maps, is characterized by the use of an analytical approach. The approach is applied to explicitly obtain the average squared action as a function of the (discrete) time and the parameters controlling nonlinearity and dissipation. This allows to obtain a set of critical exponents so far obtained numerically in the literature. The theoretical predictions are verified by extensive numerical simulations. We conclude that all possible dynamical cases, independently on the map parameter values and initial conditions, collapse into the universal exponential decay of the properly normalized average squared action as a function of a normalized time. The formalism developed here can be extended to many other different types of mappings therefore making the methodology generic and robust.

Border Collision Bifurcations in a Generalized Model of Population Dynamics

We analyze the dynamics of a generalized discrete time population model of a two-stage species with recruitment and capture. This generalization, which is inspired by other approaches and real data that one can find in literature, consists in considering no restriction for the value of the two key parameters appearing in the model, that is, the natural death rate and the mortality rate due to fishing activity. In the more general case the feasibility of the system has been preserved by posing opportune formulas for the piecewise map defining the model. The resulting two-dimensional nonlinear map is not smooth, though continuous, as its definition changes as any border is crossed in the phase plane. Hence, techniques from the mathematical theory of piecewise smooth dynamical systems must be applied to show that, due to the existence of borders, abrupt changes in the dynamic behavior of population sizes and multistability emerge. The main novelty of the present contribution with respect to the previous ones is that, while using real data, richer dynamics are produced, such as fluctuations and multistability. Such new evidences are of great interest in biology since new strategies to preserve the survival of the species can be suggested.

Crises in a dissipative bouncing ball model

The dynamics of a bouncing ball model under the influence of dissipation is investigated by using a two-dimensional nonlinear mapping. When high dissipation is considered, the dynamics evolves to different attractors. The evolution of the basins of the attracting fixed points is characterized, as we vary the control parameters. Crises between the attractors and their boundaries are observed. We found that the multiple attractors are intertwined, and when the boundary crisis between their stable and unstable manifolds occurs, it creates a successive mechanism of destruction for all attractors originated by the sinks. Also, a physical impact crisis is described, an important mechanism in the reduction of the number of attractors.

On a discrete-time model with replicator dynamics in renewable resource exploitation

We consider a discrete-time version of the model proposed by Lamantia and Radi [15] to describe a fishery where a population regulated by a logistic growth function is exploited by a pool of agents that can choose, at each time period, between two different harvesting strategies according to a profit-driven evolutionary selection rule. The resulting discrete dynamical system, represented by a two-dimensional nonlinear map, is characterized by the presence of invariant lines on which the dynamics are governed by one-dimensional restrictions that represent pure, i.e. adopted by all players, strategies. However, interesting dynamics related to interior attractors, where players playing both strategies coexist, are evidenced by analytical as well as numerical methods that reveal local and global bifurcations.

Coexistence of equilibria in a New Keynesian model with heterogeneous beliefs

The recent macroeconomic literature has been stressing the importance of considering heterogeneous expectations while addressing monetary policy. In this paper we consider a standard New Keynesian model, described by a two-dimensional nonlinear map, to analyze the bifurcation structure when agents have heterogeneous expectations and update their beliefs based on past performance. Depending on the degree of reactivity of the monetary policy to inflation and output deviations from the target equilibrium, different kind of dynamics may occur. We find that multiple equilibria and complicated dynamics, associated to codimension-2 bifurcations, may arise even if the monetary policy is set to respond more than point for point to inflation, as the Taylor principle prescribes. We show that if the monetary policy accommodates for a sufficient degree of output stabilization, complicated dynamics can be avoided and the number of coexisting equilibria reduces.

Bifurcations and Chaos Generation from 1D or 2D Circuits Including Switches

Generation of chaos is of the highest interest for many kind of applications as secure transmissions, image processing or telecommunications. In order to obtain chaotic signals that can be used in applications, simple circuits including switches have been considered those last years. Their interest is of two types: first, they belong to the class of hybrid systems that have recently attracted a great interest, secondly, they permit to obtain chaos in a very easy way. Such circuits are very easy to implement and robust chaos can be obtained, depending upon parameter values. For this aim, it is necessary to study and understand the bifurcation structures of the circuit model. In this paper, we propose two kinds of chaos generators obtained from simple RC circuits including switches managed using a clock (impulse waveform) and the charging/discharging of the capacitors. Our models are given via one-dimensional (1D) or two-dimensional (2D) nonlinear maps. We present the bifurcation studies permitting to understand the evolution of the behaviour of our systems and the appearance of chaos.

Two-dimensional nonlinear map characterized by tunable Lévy flights.

After recognizing that point particles moving inside the extended version of the rippled billiard perform Lévy flights characterized by a Lévy-type distribution P(l)∼l(-(1+α)) with α=1, we derive a generalized two-dimensional nonlinear map Mα able to produce Lévy flights described by P(l) with 0<α<2. Due to this property, we call Mα the Lévy map. Then, by applying Chirikov's overlapping resonance criteria, we are able to identify the onset of global chaos as a function of the parameters of the map. With this, we state the conditions under which the Lévy map could be used as a Lévy pseudorandom number generator and furthermore confirm its applicability by computing scattering properties of disordered wires.

Nonlinear chaos - based security solution for fingerprint data during communication

Protecting privacy for exchanging information through the media has been a topic researched by many people. This work presents a security solution for transmitting fingerprint images over insecure channels. Here security is provided by an encryption technique based on reversible hidden transform (RHT), fractional wavelet packet transform (FrWPT), chaotic map and singular value decomposition (SVD). This scheme proposes the use of coupled two-dimensional piecewise nonlinear chaotic map (CTPNCM) for selecting the transform order of FrWPT. And here the inputs to this chaotic map act as the secret keys. By architecture itself this nonlinear chaotic map provides more security to the encryption scheme than the linear ones.

Dynamics in two-elevator traffic system with real-time information

Abstract We study the dynamics of traffic system with two elevators using a elevator choice scenario. The two-elevator traffic system with real-time information is similar to the two-route vehicular traffic system. The dynamics of two-elevator traffic system is described by the two-dimensional nonlinear map. An elevator runs a neck-and-neck race with another elevator. The motion of two elevators displays such a complex behavior as quasi-periodic one. The return map of two-dimensional map shows a piecewise map.

Interacting nonequilibrium systems with two temperatures

We investigate a simplified model of two fully connected magnetic systems maintained at different temperatures by virtue of being connected to two independent thermal baths while simultaneously being interconnected with each other. Using generating functional analysis, commonly used in statistical mechanics, we find exactly soluble expressions for their individual magnetization that define a two-dimensional nonlinear map, the equations of which have the same form as those obtained for densely connected equilibrium systems. Steady states correspond to the fixed points of this map, separating the parameter space into a rich set of nonequilibrium phases that we analyze in asymptotically high and low (nonequilibrium) temperature limits. The theoretical formalism is shown to revert to the classical nonequilibrium steady state problem for two interacting systems with a nonzero heat transfer between them that catalyzes a phase transition between ambient nonequilibrium states.

One-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator

A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass m, confined to bounce elastically between two rigid walls where one is described by a nonlinear van der Pol type oscillator while the other one is fixed, working as a reinjection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional nonlinear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; and (ii) the case where collisions of the particle do affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter (χ) controlling the nonlinearity of the moving wall. For large χ, a diffusion on the velocity is observed leading to the conclusion that Fermi acceleration is taking place. On the other hand, for case (ii), the motion of the moving wall is affected by collisions with the particle. However, due to the properties of the van der Pol oscillator, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicated organization.