Soliton solutions for the space-time nonlinear partial differential equations with fractional-orders

Many practical models in interdisciplinary fields can be described with the help of fractional-order nonlinear partial differential equations(NPDEs). Fractional-order NPDEs such as the space-time fractional Fokas equation, the space-time Kaup–Kupershmidt equation and the space-time fractional (2+1)-dimensional breaking soliton equation have been widely applied in many branches of science and engineering. So, finding exact traveling wave solutions are very helpful in the theories and numerical studies of such equations. More precisely, fractional sub-equation method together with the proposed technique is implemented to obtain exact traveling wave solutions of such physical models involving Jumarie’s modified Riemann–Liouville derivative. As a result, some new exact traveling wave solutions for them are successfully established. Also, (1+1)-dimensional plots and 1-dimensional plots of some of the derived solutions are given to visualize the dynamics of the considered NPDEs. The obtained results reveal that the proposed technique is quite effective and convenient for obtaining exact solutions of NPDEs with fractional-order.     

Solitary wave solutions for some nonlinear time-fractional partial differential equations

In this paper, we have studied the hybrid projective synchronisation for incommensurate, integer and commensurate fractional-order financial systems with unknown disturbance. To tackle the problem of unknown bounded disturbance, fractional-order disturbance observer is designed to approximate the unknown disturbance. Further, we have introduced simple sliding mode surface and designed adaptive sliding mode controllers incorporating with the designed fractional-order disturbance observer to achieve a bounded hybrid projective synchronisation between two identical fractional-order financial model with different initial conditions. It is shown that the slave system with disturbance can be synchronised with the projection of the master system generated through state transformation. Simulation results are presented to ensure the validity and effectiveness of the proposed sliding mode control scheme in the presence of external bounded unknown disturbance. Also, synchronisation error for commensurate, integer and incommensurate fractional-order financial systems is studied in numerical simulation.     

Pure soliton solutions of some nonlinear partial differential equations

A general approach is given to obtain the system of ordinary differential equations which determines the pure soliton solutions for the class of generalized Korteweg-de Vries equations (cf. [6]). This approach also leads to a system of ordinary differential equations for the pure soliton solutions of the sine-Gordon equation.     

Modified Kudryashov method via new exact solutions for some conformable fractional differential equations arising in mathematical biology

In this study, the modified Kudryashov method is used to construct new exact solutions for some conformable fractional differential equations. By implementing the conformable fractional derivative and compatible fractional complex transforms, the fractional generalized reaction duffing (RD) model equation, the fractional biological population model and the fractional diffusion reaction (DR) equation with quadratic and cubic nonlinearity are discussed. As an outcome, some new exact solutions are formally established. All solutions have been verified back into its corresponding equation with the aid of maple package program. We assure that the employed method is simple and robust for the estimation of the new exact solutions, and practically capable for reducing the size of computational work for solving a various class of fractional differential equations arising in applied mathematics, mathematical physics and biology.     

Exact solutions for nonlinear partial fractional differential equations

In this article,we use the fractional complex transformation to convert nonlinear partial fractional differential equations to nonlinear ordinary differential equations.We use the improved(G’/G)-expansion function method to calculate the exact solutions to the time-and space-fractional derivative foam drainage equation and the time-and space-fractional derivative nonlinear KdV equation.This method is efficient and powerful for solving wide classes of nonlinear evolution fractional order equations.     

Solitary wave solutions to nonlinear evolution equations in mathematical physics

This paper obtains solitons as well as other solutions to a few nonlinear evolution equations that appear in various areas of mathematical physics. The two analytical integrators that are applied to extract solutions are tan–cot method and functional variable approaches. The soliton solutions can be used in the further study of shallow water waves in (1+1) as well as (2+1) dimensions.     

Exact solutions of some nonlinear partial differential equations using functional variable method

The functional variable method is a powerful solution method for obtaining exact solutions of some nonlinear partial differential equations. In this paper, the functional variable method is used to establish exact solutions of the generalized forms of Klein–Gordon equation, the (2?+?1)-dimensional Camassa–Holm Kadomtsev–Petviashvili equation and the higher-order nonlinear Schrödinger equation. By using this useful method, we found some exact solutions of the above-mentioned equations. The obtained solutions include solitary wave solutions, periodic wave solutions and combined formal solutions. It is shown that the proposed method is effective and general.     

Soliton solutions of some nonlinear evolution equations with time-dependent coefficients

In this paper, we obtain exact soliton solutions of the modified KdV equation, inhomogeneous nonlinear Schrödinger equation and G(m, n) equation with variable-coefficients using solitary wave ansatz. The constraint conditions among the time-dependent coefficients turn out as necessary conditions for the solitons to exist. Numerical simulations for dark and bright soliton solutions for the mKdV equation are also given.     

A simple technique for constructing exact solutions to nonlinear differential equations with conformable fractional derivative

The modified simple equation method is an interesting technique to find new and more general exact solutions to the fractional differential equations in nonlinear sciences. In this paper, the method is applied to construct exact solutions of (2+1)-dimensional conformable time-fractional Zoomeron equation and the conformable space-time fractional EW equation.     

Painlevé analysis and integrability aspects of some nonlinear partial differential equations

A brief review of the Painlevé singularity structure analysis of some autonomous and nonautonomous nonlinear partial differential equations is discussed. We point out how the Painlevé analysis of solutions of these equations systematically provides the integrability properties of the equation. The Lax pair, Bäcklund transformation and bilinear forms are constructed from the analysis.     

Conformable variational iteration method,conformable fractional reduced differential transform method and conformable homotopy analysis method for non-linear fractional partial differential equations

In this paper, we introduce conformable variational iteration method (C-VIM), conformable fractional reduced differential transform method (CFRDTM) and conformable homotopy analysis method (C-HAM). Between these methods, the C-VIM is introduced for the first time for fractional partial differential equations (FPDEs). These methods are new versions of well-known VIM, RDTM and HAM. In addition, above-mentioned techniques are based on new defined conformable fractional derivative to solve linear and non-linear conformable FPDEs. Firstly, we present some basic definitions and general algorithm for proposal methods to solve linear and non-linear FPDEs. Secondly, to understand better, the presented new methods are supported by some examples. Finally, the obtained results are illustrated by the aid of graphics and the tables. The applications show that these new techniques C-VIM, CFRDTM and C-HAM are extremely reliable and highly accurate and it provides a significant improvement in solving linear and non-linear FPDEs.     

Auto-Bäcklund transformations and exact solutions for some nonlinear partial differential equations with nonlinear terms of any order

In this paper, by introducing some proper transformations, the applied range of the homogenous balance (HB) method is extended. With the help ofMathematica, we obtain three auto-Bäcklund transformations (BT) for the generalized Fithugh-Nagumo equation, the generalized Burgers-Fisher equation, the generalized Burgers-Huxley equation, respectively, by use of the extended HB method. From these BTs, some exact solutions for these equations are derived.     

Exp-function method for N-soliton solutions of nonlinear evolution equations in mathematical physics

In this Letter, the Exp-function method is generalized to construct N-soliton solutions of a KdV equation with variable coefficients. As a result, 1-soliton, 2-soliton and 3-soliton solutions are obtained, from which the uniform formula of N-soliton solutions is derived. It is shown that the Exp-function method may provide us with a straightforward and effective mathematical tool for generating N-soliton solutions of nonlinear evolution equations in mathematical physics.     

Optimal Gaussian solutions of nonlinear stochastic partial differential equations

We present a linearization procedure of a stochastic partial differential equation for a vector field (X _i (t,x)) (t[0, ),xR ^d ,i=l,...,n): _t X _i (t,x)=b _i (X(t, x)) +D, X _i (t, x) + _i f _i (t, x). Here is the Laplace-Beltrami operator inR ^d , and (f _i (t,x)) is a Gaussian random field with f _i (t,x)f _j (t,x) = _ij (t – t)(x – x). The procedure is a natural extension of the equivalent linearization for stochastic ordinary differential equations. The linearized solution is optimal in the sense that the distance between true and approximate solutions is minimal when it is measured by the Kullback-Leibler entropy. The procedure is applied to the scalar-valued Ginzburg-Landau model in R¹ withb ₁(z) =z - vz ³. Stationary values of mean, variance, and correlation length are calculated. They almost agree with exact ones if 1.24 ( ² ₁ ⁴ /D ₁ ^1/3:= _c . When _c , there appear quasistationary states fluctuating around one of the bottoms of the potentialU(z) = b ₁(z)dz. The second moment at the quasistationary states almost agrees with the exact one. Transient phenomena are also discussed. Half-width at half-maximum of a structure function decays liket ^–1/2 for small t. The diffusion term _x ² X accelerates the relaxation from the neighborhood of an unstable initial stateX(0,x) 0.     

Bright and dark soliton solutions for some nonlinear fractional differential equations

In this work, we propose a new approach, namely ansatz method, for solving fractional differential equations based on a fractional complex transform and apply it to the nonlinear partial space–time fractional modified Benjamin–Bona–Mahoney(m BBM) equation, the time fractional m Kd V equation and the nonlinear fractional Zoomeron equation which gives rise to some new exact solutions. The physical parameters in the soliton solutions: amplitude, inverse width, free parameters and velocity are obtained as functions of the dependent model coefficients. This method is suitable and more powerful for solving other kinds of nonlinear fractional PDEs arising in mathematical physics. Since the fractional derivatives are described in the modified Riemann–Liouville sense.     

Critical layer singularities and complex eigenvalues in some differential equations of mathematical physics

Singular differential equations are a common feature of many problems in mathematical physics. It is often the case that systems with a similar mathematical structure can arise in many different contexts. In this article, mathematically related problems are drawn from areas as diverse as hydrodynamics (with applications to oceanography and meteorology), magnetohydrodynamics and plasma physics (with applications to astrophysics and geophysics, especially solar physics, ionospheric and magnetospheric physics; also nuclear fusion devices), acoustics, electromagnetics, quantum mechanics and nuclear physics. One major unifying feature common to the problems discussed here is the existence of complex eigenvalues, often associated with so-called “classical self-adjoint” equations. No real contradiction is involved here, but the resulting wave functions are often referred to variously as “radioactive states”, “damped resonances”, “leaky waves”, “non-modal solutions” , “singular modes”, “virtual modes”, or “improper eigenfunctions”. In the hydrodynamics of shear flows, such modes are associated with the existence of “critical layers” at which a singularity occurs in the governing (ordinary) differential equation. Similar, but usually more general singular layers are known to occur in equations arising in many of the above-mentioned contexts, and it is the purpose of this review to identify the nature of these singular layers and complex eigenvalues, and the relationships that exist between the different context in which they are found, and in particular to emphasize the occurrence of and interpretation of complex eigenvalues in quantum mechanics. Thus the “exponential catastrophe” is a clearly identified and recurring theme throughout this article by virtue of the similarities that exist between the classical and quantum system discussed here. The examples quoted from quantum mechanics are simple in form, and found in many standard texts, but the virtue of including them here is twofold: the results are easy to understand and relate to the more complicated “classical” systems, and they provide a valuable didactic and pedagogic tool for those readers whose background in quantum mechanics is limited. It is also hoped that this article will be of interest to readers who wish to become more acquainted with some aspects of hydrodynamics and magnetohydrodynamics.     

The non-linear stability of front solutions for parabolic partial differential equations

For the Ginzburg-Landau equation and similar reaction-diffusion equations on the line, we show convergence ofcomplex perturbations of front solutions towards the front solutions, by exhibiting a coercive functional.     

数学物理方程中的通解问题

通过例证说明,通解法对于偏微分方程而言,其适用范围要比通常认为的大.并表明,只要适当变通,行波法就可用于有界情况.