Fractional Noether theorem and fractional Lagrange equation of multi-scale mechano-electrophysiological coupling model of neuron membrane

Noether theorem is applied to a variable order fractional multiscale mechano-electrophysiological model of neuron membrane dynamics.The variable orders fractional Lagrange equation of a multiscale mechano-electrophysiological model of neuron membrane dynamics is given.The variable orders fractional Noether symmetry criterion and Noether conserved quantities are given.The forms of variable orders fractional Noether conserved quantities corresponding to Noether symmetry generators solutions of the model under different conditions are discussed in detail,and it is found that the expressions of variable orders fractional Noether conserved quantities are closely dependent on the external nonconservative forces and material parameters of the neuron.

Fractional Action-Like Variational Problem and Its Noether Symmetries for a Nonholonomic System

For an in-depth study on the symmetric properties for nonholonomic non-conservative mechanical systems,the fractional action-like Noether symmetries and conserved quantities for nonholonomic mechanical systems are studied,based on the fractional action-like approach for dynamics modeling proposed by El-Nabulsi.Firstly,the fractional action-like variational problem is established,and the fractional action-like Lagrange equations of holonomic system and the fractional action-like differential equations of motion with multiplier for nonholonomic system are given;secondly,according to the invariance of fractional action-like Hamilton action under infinitesimal transformations of group,the definitions and criteria of fractional action-like Noether symmetric transformations and quasi-symmetric transformations are put forward;finally,the fractional action-like Noether theorems for both holonomic system and nonholonomic system are established,and the relationship between the fractional action-like Noether symmetry and the conserved quantity is given.

Noether's theorems of a fractional Birkhoffian system within Riemann-Liouville derivatives

The Noether symmetry and the conserved quantity of a fractional Birkhoffian system are studied within the Riemann–Liouville fractional derivatives. Firstly, the fractional Birkhoff＇s equations and the corresponding transversality conditions are given. Secondly, from special to general forms, Noether＇s theorems of a standard Birhoffian system are given, which provide an approach and theoretical basis for the further research on the Noether symmetry of the fractional Birkhoffian system. Thirdly, the invariances of the fractional Pfaffian action under a special one-parameter group of infinitesimal transformations without transforming the time and a general one-parameter group of infinitesimal transformations with transforming the time are studied, respectively, and the corresponding Noether＇s theorems are established. Finally, an example is given to illustrate the application of the results.

Fractional Optical Solitons and Fractional Noether’s Theorem with Ortigueira’s Centered Derivatives

This paper shows that the centered fractional derivatives introduced by Manuel Duarte Ortigueira in 2006 are useful in the description of optical solitons. It is shown that we can construct a fractional extension of the nonlinear Schrödinger (NLS) equation which incorporates Ortigueira’s derivatives and has soliton solutions. It is also shown that this fractional NLS equation has a Lagrangian density and can be derived from a variational principle. Finally, a fractional extension of Noether’s theorem is formulated to determine the conserved quantities associated to the invariances of the action integral under infinitesimal transformations.

Fractional Noether's Theorems for El-Nabulsi's Fractional Birkhoffian Systems in Terms of Riemann-Liouville Derivatives

The fractional Pfaffian variational problem and Noether’s theorems were investigated in terms of Riemann-Liouville derivatives on the basis of El-Nabulsi fractional model.The problem of the calculus of variations with fractional derivatives is a hot topic recently.Firstly,within Riemann-Liouville derivatives,the ElNabulsi Pfaffian variational problem was presented,the fractional Pfaff-Birkhoff-d’Alembert principle was established,and the fractional Birkhoff equations and the corresponding transversality conditions were obtained.Then,the Noether’s theorems in terms of Riemann-Liouville derivatives for the Birkhoffian system on the basis of El-Nabulsi fractional model are investigated under the special and the general transformations respectively.Finally,an example is given to illustrate the methods and results appeared in this paper.

Variational Calculus With Conformable Fractional Derivatives

Invariant conditions for conformable fractional problems of the calculus of variations under the presence of external forces in the dynamics are studied. Depending on the type of transformations considered, different necessary conditions of invariance are obtained. As particular cases, we prove fractional versions of Noether's symmetry theorem. Invariant conditions for fractional optimal control problems, using the Hamiltonian formalism, are also investigated. As an example of potential application in Physics, we show that with conformable derivatives it is possible to formulate an Action Principle for particles under frictional forces that is far simpler than the one obtained with classical fractional derivatives.

Noether Theorem for Fractional Singular Systems

Noether theorems for two fractional singular systems are discussed.One system involves mixed integer and Caputo fractional derivatives,and the other involves only Caputo fractional derivatives.Firstly,the fractional primary constraints and the fractional constrained Hamilton equations are given.Then,the fractional Noether theorems of the two fractional singular systems are established,including the fractional Noether identities,the fractional Noether quasi-identities and the fractional conserved quantities.Finally,the results obtained are illustrated by two examples.

基于按正弦周期律拓展的分数阶积分的变分问题的Noether定理

基于按正弦周期律拓展的分数阶积分的类分数阶动力学建模方法,研究完整系统的类分数阶Noether对称性和守恒量。首先,基于按正弦周期律拓展的分数阶积分,建立了类分数阶变分问题,导出了类分数阶d'Alembert-Lagrange原理,给出了类分数阶Euler-Lagrange方程;其次,基于类分数阶Hamilton作用量在无限小群变换下的不变性,提出了类分数阶Noether对称变换和Noether准对称变换的定义和判据;最后,建立了类分数阶Noether定理,揭示了系统的Noether对称性与守恒量之间的关系,并举例说明结果的应用。

基于El-Nabulsi分数阶模型的广义Birkhoff系统Noether对称性研究

为了进一步揭示力学系统的对称性与守恒量之间的内在关系,基于El-Nabulsi分数阶模型提出并研究了广义Birkhoff系统的Noether定理。首先,提出分数阶广义El-Nabulsi-PfaffBirkhoff原理,建立广义El-Nabulsi-Birkhoff方程。其次,基于El-Nabulsi-Pfaff作用量在无限小变换下的不变性,给出广义Birkhoff系统Noether对称性的定义和判据。最后,提出广义Birkhoff系统的Noether定理。该文研究结果可进一步应用于完整和非完整约束系统。

相空间中类分数阶变分问题的Noether对称性与守恒量

基于El-Nabulsi提出的分数阶动力学建模方法,即类分数阶变分方法,研究相空间中类分数阶变分问题与Noether对称性和守恒量。建立了相空间中类分数阶变分问题,得到了类分数阶Hamilton正则方程;基于类分数阶Hamilton作用量在无限小群变换下的不变性,提出了相空间中类分数阶Noether(准)对称变换的定义和判据;给出了类分数阶Hamilton系统的Noether定理,建立了类分数阶Noether对称性与守恒量之间的内在关系,并举例说明结果的应用。

CaputoΔ型分数阶时间尺度Noether定理

时间尺度理论将微分方程理论和差分方程理论融合于一体,而分数阶微积分可以为实际问题提供更为切合的模型.分数阶时间尺度微积分因能统一研究连续分数阶系统和离散分数阶系统而备受关注.结合时间尺度和分数阶微积分,研究含CaputoΔ导数的分数阶时间尺度Noether定理,为研究复杂系统动力学行为提供了一个新的视角.首先,回顾了分数阶时间尺度积分和导数的定义.其次,根据所提出的CaputoΔ型分数阶时间尺度Hamilton原理,导出了分数阶时间尺度Lagrange方程.在特定条件下,此方程可退化为时间尺度Lagrange方程、Caputo型分数阶Lagrange方程和经典Lagrange方程.进一步地,在特殊无限小变换和一般无限小变换两种情形下,分别给出了CaputoΔ型分数阶时间尺度Noether对称性的定义和判据.继而,提出并证明了特殊无限小变换下的分数阶时间尺度Noether定理(定理1)和一般无限小变换下的分数阶时间尺度Noether定理(定理2).当α=1时,定理1则退化为特殊无限小变换下的经典时间尺度Noether定理,并且定理2成为利用广义Jost方法所得到的时间尺度Noether定理.此外,当T=R时,定理2还可退化为Caputo型分数阶Noether定理.最后,以平面上的分数阶时间尺度Kepler问题和单自由度分数阶时间尺度线性振动系统为例来验证定理的正确性.

事件空间中非保守系统的一类拟分数阶Noether定理

为了深入研究非保守动力学系统的对称性和守恒量,提出并研究事件空间中基于周期律拓展的拟分数阶模型的Noether定理。首先提出事件空间中基于按周期律拓展的分数阶积分的El-Nabulsi分数阶变分问题,求解出该模型下完整非保守系统与非完整非保守系统的运动微分方程;其次,基于作用量泛函在无限小变换下的不变性,建立Noether对称变换和Noether准对称变换的定义和判据;最后,提出并证明了事件空间中基于按周期律拓展的拟分数阶模型的Noether定理,并给出两个算例以说明定理的应用。

基于广义分数阶算子Birkhoff系统Noether定理

本文就广义分数阶导数算子,提出两个新的“变换公式”,将其应用于分数阶Birkhoff系统,并导出分数阶Birkhoff系统的Noether定理.这个定理提供了一个计算分数阶Birkhoff系统运动常数的方法,克服了先前文献研究分数阶动力学系统守恒量的一些缺陷,并在文末给出两个推论.

事件空间中基于El-Nabulsi指数律拟分数阶模型的Noether定理

为了进一步研究非保守系统的动力学行为,揭示动力学系统的对称性和守恒量的联系,提出并研究事件空间中基于El-Nabulsi指数律拟分数阶模型的Noether定理。首先,提出事件空间中基于指数律拓展的分数阶积分的El-Nabulsi拟分数阶变分问题,建立了完整系统与非完整系统的运动微分方程;其次,基于该模型下作用量泛函在无限小变换下的不变性,给出了Noether对称变换和Noether准对称变换的定义和判据;最后,提出并证明了事件空间中基于El-Nabulsi指数律拟分数阶模型的Noether定理,并举例说明结果的应用。

Noether's Symmetries and Its Inverse for Fractional Logarithmic Lagrangian Systems

In this paper, Noether's theorem and its inverse theorem are proved for the fractional variational problems based on logarithmic Lagrangian systems. The Hamilton principle of the systems is derived. And the definitions and the criterions of Noether's symmetry and Noether's quasi-symmetry of the systems based on logarithmic Lagrangians are given. The intrinsic relation between Noether's symmetry and the conserved quantity is established. At last an example is given to illustrate the application of the results.