Issue |
Wuhan Univ. J. Nat. Sci.
Volume 29, Number 6, December 2024
|
|
---|---|---|
Page(s) | 547 - 557 | |
DOI | https://doi.org/10.1051/wujns/2024296547 | |
Published online | 07 January 2025 |
Mathematics
CLC number: O316
Symmetries of Fractional Constrained Hamiltonian System Described by the Singular Lagrangian
由奇异Lagrange函数描述的约束Hamilton系统的对称性
School of Mathematical Sciences, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu, China
† Corresponding author. E-mail: songchuanjingsun@mail.usts.edu.cn
Received:
28
September
2023
Singular systems within combined fractional derivatives are established. Firstly, the fractional Lagrange equation is analyzed. Secondly, the fractional primary constraint is given. Thirdly, the Noether and Lie symmetry methods of fractional constrained Hamiltonian system are studied. Finally, the obtained results are illustrated with an example.
摘要
基于联合分数阶导数建立了奇异系统。首先,分析了分数阶Lagrange方程;其次,给出了分数阶初级约束;第三,研究了分数阶约束Hamilton系统的Noether对称性和Lie对称性方法;最后,举例对所得结果进行阐述。
Key words: combined fractional derivative / constrained Hamilton equation / conserved quantity / Noether symmetry / Lie symmetry
关键字 : 联合分数阶导数 / 约束Hamilton方程 / 守恒量 / Noether对称性 / Lie对称性
Cite this article: WANG Cai, SONG Chuanjing. Symmetries of Fractional Constrained Hamiltonian System Described by the Singular Lagrangian[J]. Wuhan Univ J of Nat Sci, 2024, 29(6): 547-557.
Biography: WANG Cai, male, Master candidate, research direction: analytical mechanics. E-mail: 2231577893@qq.com
Foundation item: Supported by the National Natural Science Foundation of China (12172241, 12272248) and the Qing Lan Project of Colleges and Universities in Jiangsu Province
© Wuhan University 2024
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
0 Introduction
With the continuous development of mathematics and physics, fractional calculus has been widely discussed in recent years. Fractional-order model enables us to describe complex dynamics and physical behaviors better. Fractional calculus has important applications in fluid mechanics, nuclear magnetic resonance imaging, mechanics of complex viscoelastic materials, and so on[1-5]. Riewe[6,7] introduced fractional derivatives to deal with dissipative forces. After that, research on fractional derivatives has mainly focused on the left and right Riemann-Liouville, the left and right Caputo, the Riesz-Riemann-Liouville and the Riesz-Caputo fractional derivatives. Recently, a more general definition of fractional derivative, which is called combined fractional derivative, was introduced. For example, Malinowska and Torres[8] studied fractional calculus of variations based on a combined Caputo fractional derivative. Zhang[9] established the fractional differential equations of motion using a combined Riemann-Liouville fractional derivative. In 2015, Luo et al[10] presented the dynamics of a Birkhoffian system with both combined Caputo fractional derivatives and combined Riemann-Liouville fractional derivatives. Specifically, the four derivatives mentioned above are all special cases of the combined fractional derivative. Therefore, the combined fractional derivative is general.
The singular system refers to the procedure described by the singular Lagrangian. The singular system plays a vital role in modern quantum field theory, such as gravity theory, string (membrane) field theory, Yang-Mills theory, supersymmetry, and supergravity[11]. When a singular system is described by the canonical variables, there are several inherent constraints. In this case, the system is called the constrained Hamiltonian system, which is essential in condensed matter theory, gauge field theory and many other aspects[12-14].
Noether symmetry and Lie symmetry are two commonly used methods to study constrained mechanics systems. Noether symmetry was put forward by Noether[15]. Lie symmetry was introduced by Lutzky[16]. Then Noether and Lie symmetry were studied further[17,18]. Particularly, for singular systems, Lie symmetry and conserved quantity based on Riemann-Liouville fractional derivative[19], Noether symmetry and conserved quantity based on mixed order derivative and Caputo fractional derivative[20] are studied. Besides, based on the combined fractional derivative, Noether symmetry and conserved quantity for the Birkhoffian system are studied[21]. In this paper, we intend to study Noether symmetry and Lie symmetry for the singular system based on the combined fractional derivative.
Section 1 gives the preliminaries. In Section 2, the fractional Lagrange equation is analyzed using the combined fractional derivative. In Section 3 and Section 4, the fractional primary constraint is established and the Hamilton equation of the fractional constraint is given. In Section 5 and Section 6, the fractional Noether symmetry, Lie symmetry, and conserved quantities are studied, respectively. An example is given in Section 7 and the conclusion is given in Section 8.
1 Preliminaries
The following preliminaries are about the combined fractional derivatives, which can be seen in Ref. [8], Ref. [22] and Ref. [23]. The combined fractional derivative includes the combined Riemann-Liouville fractional derivative and the combined Caputo fractional derivative.
The combined Riemann-Liouville fractional derivative and combined Caputo fractional derivative are
where , , and are the left and right Riemann-Liouville and Caputo fractional derivatives, , , .
Under the condition , we have
Additionally, the fractional partial integral formulae are
where represents the integer order derivative.
It should be noted that in this paper, we set .
2 Fractional Lagrange Equation
In this section, the fractional variational problems under combined fractional derivatives are studied.
We give a function
where , , , , and the Lagrangian is assumed to be a function. If is an extremal of Eq. (11), we obtain
where is a small parameter, , . Further, we get
Using fractional partial integral formulae (Eqs. (5) and (6)) in the second terms of Eq. (13), we obtain
where , . Substituting Eq. (14) into Eq. (13), we obtain
According to the fundamental lemma of variational calculation[24], we can deduce that
Eq. (16) is called the fractional Lagrange equation within the combined Riemann-Liouville fractional derivative.
The fractional Lagrange equation has another form, which can be obtained from Eqs. (3), (4), (7), (8) and (13) as
Similarly, the fractional Lagrange equation within the combined Caputo fractional derivative can also be obtained as
where the Lagrangian , is assumed to be a function,, .
Remark 1 Eqs. (16) and (18) are general and universal, so we can select different values of to get different results.
3 Fractional Primary Constraint
This section presents fractional primary constraints within the combined Riemann-Liouville fractional derivative and combined Caputo fractional derivative.
Define fractional generalized momentum and Hamiltonian as
Here, we consider that the is singular, meaning that only a portion of the terms , can be solved. In this case, we assume the number is , .
Firstly, when , we have
where , , . Substituting Eq. (21) into Eq. (19), we have
If , Eq. (22) obviously holds. If , we have
where , , . Another form of Eq. (23) is
where , , .
Secondly, when , cannot be solved. Therefore, from Eq. (19), we have
From Eq. (24) and Eq. (26), we can obtain
Eq. (27) is called fractional primary constraint within a combined Riemann-Liouville fractional derivative.
Similarly, we can define
The fractional primary constraint within the combined Caputo fractional derivative can be obtained as
Remark 2 According to the definition of the fractional generalized momenta (Eqs. (19) and (28)) rather than the fractional Euler-Lagrange equations (Eqs. (16) and (18)), the fractional primary constraints (Eqs. (27) and (30)) are obtained.
4 Fractional Constrained Hamilton Equation
Firstly, the fractional constrained Hamilton equation within the combined Riemann-Liouville fractional derivative is studied.
From Eq. (20), we obtain
Besides, because of the Hamiltonian , we have
It follows from Eqs. (31) and (32) that
Making use of Eqs. (16) and (19), the term in Eq. (33) can be replaced by , thus we have
where , . When the system (Eq. (16)) is singular, we have
It follows from Eqs. (34) and (35) that
Eq. (36) is called fractional constrained Hamilton equation within a combined Riemann-Liouville fractional derivative.
Similarly, we can also get the Hamilton equation with fractional constraints within the combined Caputo fractional derivative
Remark 3 Because of the various values of , different results can be obtained from Eqs. (36) and (37).
According to the above method of establishing the Hamilton equation with fractional constraints, it is very important to solve the Lagrange multiplier. Next, we will calculate the Lagrange multiplier by fractional Poisson bracket.
Let , , , , then we define
Then we have
and
From Eqs. (39) and (40), the Lagrange multipliers can be calculated.
5 Noether Theorem
Definition 1 A quantity is called a conserved quantity if and only if .
5.1 Noether Theorem within the Combined Riemann-Liouville Fractional Derivative
The Hamilton action within the combined Riemann-Liouville fractional derivative is
The infinitesimal transformations are
Namely,
where is a small parameter, , , and are infinitesimal generators, and means the higher order of .
Letting be the linear part of , and without considering the higher order of , we obtain
where and . Let , then Eq. (44) gives
Equation (45) is called the fractional Noether identity within the combined Riemann-Liouville fractional derivative.
Theorem 1 If , , and satisfy Eq. (45), then there exists a conserved quantity
for the system within the combined Riemann-Liouville fractional derivative.
Proof Using Eqs. (27), (36), and (45), we have
The proof is completed.
5.2 Noether Theorem within the Combined Caputo Fractional Derivative
The Hamilton action within the combined Caputo fractional derivative is
The infinitesimal transformations are
Namely,
where is a small parameter, , , and are infinitesimal generators. Letting , we have
Equation (50) is called fractional Noether identity within a combined Caputo fractional derivative.
Theorem 2 If , , and satisfy Eq. (50), then there exists a conserved quantity
for the system within a combined Caputo fractional derivative.
Proof Using Eqs. (30), (37), and (50), it is easy to obtain
The proof is completed.
6 Lie Symmetry Conserved Quantity
6.1 Lie Symmetry Conserved Quantity within the Combined Riemann-Liouville Fractional Derivative
Eq. (36) can be expressed as
We then study Eqs. (52) and (53) under the infinitesimal transformations (Eq. (43)). For Eq. (52), we obtain
where
The fractional primary constraint (Eq. (27)) gives
Therefore, we have
and
Equations (57) and (58) are called the determined equations within the combined Riemann-Liouville fractional derivative, and Eq. (59) is called the limited equation within the combined Riemann-Liouville fractional derivative.
Besides, if we consider the deduction process of the system (Eq. (36)), an extra additional limited equation
can be obtained. Then we have
Theorem 3 For the system within the combined Riemann-Liouville fractional derivative (Eq. (36)), when Eqs. (45), (57) and (58) are satisfied, Eq. (46) gives a Lie symmetry conserved quantity; when Eqs. (45), (57)-(59) are satisfied, Eq. (46) gives a weak Lie symmetry conserved quantity; when Eqs. (45), (57)-(60) are satisfied, Eq. (46) gives a strong Lie symmetry conserved quantity.
6.2 Lie Symmetry Conserved Quantity within the Combined Caputo Fractional Derivative
Eq. (37) can be expressed as
Using the similar way, we can obtain the determined equations within the combined Caputo fractional derivative
the limited equation within the combined Caputo fractional derivative
and the additional limited equation within the combined Caputo fractional derivative
where . Then we have
Theorem 4 For the system within the combined Caputo fractional derivative (Eq. (37)), when Eqs. (50), (63) and (64) are satisfied, Eq. (51) gives a Lie symmetry conserved quantity; when Eqs. (50), (63)-(65) are satisfied, Eq. (51) gives a weak Lie symmetry conserved quantity; when Eqs. (50), (63)-(66) are satisfied, Eq. (51) gives a strong Lie symmetry conserved quantity.
7 An Example
The singular Lagrangian is
Try to study its Noether symmetry and conserved quantity.
From Eqs. (19) and (20), we can obtain
Then Eq. (27) gives two fractional primary constraints
From Eq. (39), we obtain
Then, using Eq. (36), the fractional constrained Hamilton equation within the combined Riemann-Liouville fractional derivative is
From Noether identity (Eq. (45)), we have
Then we can verify that
satisfy Eq. (74). Therefore, we have
Specially, we degenerate the above fractional order to the integer order, namely , so we can get
If , and let the trajectory of can be drawn as follows.
It follows from Fig. 1 that is a constant.
Fig. 1 The trajectory of |
8 Conclusion
Fractional calculus has important applications in various fields, and it is also a research hotspot. In this paper, based on the combined Riemann-Liouville fractional derivative and combined Caputo fractional derivative, we establish Noether theorem and Lie theorem for the fractional constrained Hamiltonian system. Besides, Noether identity, determined equation, limited equation and additional limited equation are presented.
In this paper, Noether-type conserved quantity is obtained from Lie symmetry, whether the Lie symmetry of the system can lead to another conserved quantity, called Hojman conserved quantity, remains to be studied. At the same time, Mei symmetry is also an effective method to solve the differential equation. Therefore, Mei symmetry is also a future research direction.
References
- Oldham K B, Spanier J. The Fractional Calculus [M]. New York: Academic Press, 1974. [MathSciNet] [Google Scholar]
- Luo S K. Analytical mechanics method of fractional dynamics and its applications [J]. Journal of Dynamics and Control, 2019, 17(5): 432-438. [Google Scholar]
- Yin Y D, Zhao D M, Liu J L, et al. Study on the rate dependency of acrylic elastomer based fractional viscoelastic model [J]. Chinese Journal of Theoretical and Applied Mechanics, 2022, 54(1): 155-163. [Google Scholar]
- Si H, Zheng Y A. Adaptive predictive synchronization of fractional order chaotic systems [J]. Journal of Dynamics and Control, 2021, 19(5): 8-12(Ch). [Google Scholar]
- Song C J. Generalized fractional forced Birkhoff equations [J]. Journal of Dynamics and Control, 2019, 17(5): 446-452. [Google Scholar]
- Riewe F. Nonconservative Lagrangian and Hamiltonian mechanics [J]. Phys Rev E, 1996, 53(2): 1890-1899. [CrossRef] [MathSciNet] [PubMed] [Google Scholar]
- Riewe F. Mechanics with fractional derivatives [J]. Phys Rev E, 1997, 55(3): 3581-3592. [NASA ADS] [CrossRef] [MathSciNet] [Google Scholar]
- Malinowska A B, Torres D F M. Fractional calculus of variations for a combined Caputo derivative [J]. Fract Calc Appl Anal, 2011, 14(4): 523-537. [Google Scholar]
- Zhang Y. Fractional differential equations of motion in terms of combined Riemann-Liouville derivatives [J]. Chin Phys B, 2012, 21(8): 84502. [Google Scholar]
- Luo S K, Xu Y L. Fractional Birkhoffian mechanics [J]. Acta Mech, 2015, 226(3): 829-844. [CrossRef] [MathSciNet] [Google Scholar]
- Li Z P. Classical and Quantal Dynamics of Constrained Systems and Their Symmetrical Properties [M]. Beijing: Beijing Polytechnic University Press, 1993(Ch). [Google Scholar]
- Dirac P A M. Lecture on Quantum Mechanics [M]. New York: Yeshiva University, 1964. [Google Scholar]
- Li Z P. Contrained Hamiltonian Systems and Their Symmetrical Properties [M]. Beijing: Beijing Polytechnic University Press, 1999. [Google Scholar]
- Li Z P, Jiang J H. Symmetries in Constrained Canonical Systems [M]. Beijing: Science Press, 2002. [Google Scholar]
- Noether A E. Invariante variationsprobleme [J]. Nachrichten von der Gesellschaft der Gesellschaft der Wissenschaften zu Göttingen, Mathematisch-Physikalische Klasse, 1918, KI(2): 235-257. [Google Scholar]
- Lutzky M. Dynamical symmetries and conserved quantities [J]. Journal of Physics A: Mathematical and General, 1979, 12(7): 973-981. [NASA ADS] [CrossRef] [MathSciNet] [Google Scholar]
- Mei F X, Wu H B. Dynamics of Constrained Mechanical Systems [M]. Beijing: Beijing Institute of Technology Press, 2009. [Google Scholar]
- Mei F X. Analytical Mechanics (II) [M]. Beijing: Beijing Institute of Technology Press, 2013. [Google Scholar]
- Song C J, Wang J H. Conserved quantity for fractional constrained Hamiltonian system [J]. Wuhan University Journal of Natural Sciences, 2022, 27(3): 201-210. [CrossRef] [EDP Sciences] [Google Scholar]
- Song C J, Zhai X H. Noether theorem for fractional singular systems [J]. Wuhan University Journal of Natural Sciences, 2023, 28(3): 207-216. [CrossRef] [EDP Sciences] [Google Scholar]
- Song C J, Zhang Y. Noether symmetry and conserved quantity for fractional Birkhoffian mechanics and its applications [J]. Frac Cal Appl Anal, 2018, 21(2): 509-526. [CrossRef] [MathSciNet] [Google Scholar]
- Podlubny I. Fractional Differential Equations [M]. San Diego: Academic Press, 1999. [Google Scholar]
- Wu Q, Huang J H. Fractional Order Calculus [M]. Beijing: Tsinghua University Press, 2016(Ch). [Google Scholar]
- Gelfand I M, Fomin S V. Calculus of Variations [M]. London: Prentice-Hall, 1963. [Google Scholar]
All Figures
Fig. 1 The trajectory of | |
In the text |
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.