Skip to main content

All Questions

Filter by
Sorted by
Tagged with
27 votes
4 answers
13k views

Hamiltonian, Lagrangian and Newton formalism of mechanics

If my thinking is wrong please let me know. I have little knowledge on beyond-college physics. For research purposes, I read a few introductions to these three formalisms of classical mechanics [1,2,...
Henry.L's user avatar
  • 8,071
9 votes
2 answers
648 views

An algebraic Hamiltonian vector field with a finite number of periodic orbits(1)

Edit: The previous version of this question contained 2 part. In this new version, I deleted the first part and move it to a new question. Is There a polynomial Hamiltonian $H(x,y,z,w)=zP(x,y)+wQ(...
Ali Taghavi's user avatar
9 votes
1 answer
728 views

When does a Lagrangian dynamical system have an equivalent Hamiltonian description?

Let a Lagrangian dynamical system with $n$ degrees of freedom and configuration space $\mathbb{R}^n$ (i.e. phase space $\mathbb{R}^{2n}$), which is described by $L=L(q_{i},\dot{q}_{i},t)$, $i=1,2,......
Konstantinos Kanakoglou's user avatar
7 votes
1 answer
719 views

Integrable systems and Arnol'd - Liouville theorem

A system with a $2n$-dimensional phase space is Liouville-integrable if it admits $n$ independent first intgrals in involution. Here integrable means that you can, in some way, solve the equations of ...
ablagi's user avatar
  • 71
7 votes
1 answer
267 views

Uniqueness of Birkhoff Normal Form and KAM theory for Symplectomorphims

I am starting to work with Hamiltonian Dynamics and I have been taking a look at some of the basic stuff in KAM theory. I have posted part of this question at MSE but as I did not get any response I ...
Frank Trujillo's user avatar
6 votes
2 answers
3k views

Poincaré recurrence and its implications for statistical physics and the arrow of time

A very important theorem in mathematical physics is Poincaré’s recurrence theorem. As you recall, this theorem states that given a dynamical system $(M , \phi , \mu)$ with $ \mu M < +\infty$, for ...
display llvll's user avatar
6 votes
0 answers
469 views

An algebraic Hamiltonian vector field with a finite number of periodic orbits (2)

Is there a polynomial Hamiltonian $H:\mathbb{R}^{4}\to \mathbb{R}$ such that the number of nontrivial periodic orbits of the corresponding Hamiltonian vector field $X_{H}$ is finite but different ...
Ali Taghavi's user avatar
4 votes
3 answers
668 views

Reference Request: KAM Theory

I intend to learn KAM Theory. Could you please suggest me a good book on KAM Theory to begin with, where main results are discussed with complete proofs. Thank you.
4 votes
1 answer
235 views

Contradiction between fixed points of a hamiltonian diffeomorphism of a torus and quasi-periodic motion on a torus

Again a very simple question. I currently hold two contradictory ideas in my head 1) A hamiltonian diffeomorphism of a torus necessarily has fixed points 2) most hamiltonian actions on a torus in an ...
R Mary's user avatar
  • 989
4 votes
1 answer
235 views

Dynamical analogue of Morse theory

Is there a Hamiltonian $H:\mathbb{R}^{2n} \to \mathbb{R}$ with the following property: For two regular values $a<b$ for which $[a,b]$ consists of regular values, the dynamics of $X_H$ on $H^{...
Ali Taghavi's user avatar
4 votes
1 answer
326 views

Some dynamical and Bundle questions arising from certain map $P:TS^{n}\to S^{n}$

Define the map $$P:TS^{n}\to S^{n} \;\;\;\text{by}\;\; P((x,v))=\frac{x+v}{\parallel x+v \parallel}$$ where $$TS^{n}=\{(x,v)\in S^{n} \ \times \mathbb{R}^{n+1}\mid v \perp x \}$$ This map is ...
Ali Taghavi's user avatar
4 votes
1 answer
299 views

Symplectic forms and sign of eigenvalues

This question has come out while reading J. Moser "New Aspects in the Theory of Stability of Hamiltonian Systems". I'm particularly interested to the Appendix, where one investigates the stability of ...
AndreaPaco's user avatar
4 votes
0 answers
104 views

Why can every twist map be realized as the time-1 map of a time-dependent Hamiltonian?

if have problems getting my head around the following claim made by Moser in "Monotone twist mappings and the calculus of variations" and Gole in "Symplectic twist maps". Setting: Let $F : \mathbb{R}...
ompus's user avatar
  • 41
3 votes
1 answer
197 views

Exact solution to a periodic linear ODE sought

We have been studying a Hamiltonian system that possesses a one-parameter family of periodic orbits, depending on the energy level $h$. We "know" via various non-rigorous means that these ...
Roy Goodman's user avatar
3 votes
1 answer
679 views

Perturbed vs. unperturbed Hamiltonian system

Let's take a time-periodic Hamiltonian $H(t,x,y)$ on $\mathbb{R}^2$ and apply an arbitrarily small time-independent perturbation to $H$ via $$ \tilde H (t,x,y) = H(t,x,y) + \epsilon V(x,y), $$ where $...
eddard's user avatar
  • 81
3 votes
0 answers
143 views

Is composition of discrete Hamiltonian flows integrable?

Consider $\Bbb{R}^2$ with the usual symplectic form $$\omega = dx \wedge dy$$ For a function $H \colon \Bbb{R}^2 \to \Bbb{R}$, let $X_H$ be the Hamiltonian vector field. Then the map $\Bbb{R}^2 \to \...
Nick's user avatar
  • 213
3 votes
0 answers
245 views

Periodic orbit for certain Hamiltonian on the tangent bundle

In this question a nontrivial periodic orbit is a periodic orbit which is not a singular point. Let $p: \mathbb{R}^n \to \mathbb{R}$ be a ...
Ali Taghavi's user avatar
2 votes
1 answer
102 views

On the existence of regular orbit cylinders

Let $(M,\omega,H)$ be a Hamiltonian system and assume that $\gamma$ is a periodic orbit on a regular energy hypersurface. Then the regular orbit cylinder theorem (see for example Abraham/Marsden: ...
TheGeekGreek's user avatar
2 votes
0 answers
101 views

Persistence of KAM tori as a function of dimension

I have tried posting this question in MSE, but I think it might be too technical so I'm trying again here. In KAM theory one tries to describe the persistence of quasi-periodic motion when an ...
QuantumBrick's user avatar
2 votes
0 answers
129 views

Is the interpolating Hamiltonian flow of an exact near-identity symplectic map globally defined?

It is well-known that an analytic near-identity map $\bar{x} = F_{\epsilon}(x) = x + \epsilon f(x) + O(\epsilon^{2})$ may be embedded into the flow of a differential equation, and if that map is ...
Vitaly's user avatar
  • 21
2 votes
0 answers
191 views

Geometric properties of solutions of Hamiltonian system

Context : We are interested in the following dynamic with state $(q,\varphi)$ $$ \dot q = \varepsilon F(q,\varphi), \quad \dot \varphi = \omega(q) + \varepsilon G(q,\varphi) $$ ($\varepsilon >0$ ...
Smilia's user avatar
  • 141
2 votes
0 answers
143 views

Is it true that a nondegenerate minimizing periodic orbit of mechanical Hamiltonian system is hyperbolic

Consider mechanical Hamiltonian system of the form $$H(p,q)=\dfrac{\Vert p\Vert^2}{2}+V(q),\quad (q,p)\in T^*\mathbb T^n.$$ Here we suppose the periodic orbit $\gamma$ minimizes the Lagrangian ...
John Galt's user avatar
  • 197
1 vote
0 answers
108 views

Stability of rigid bodies spinning around $z$-axis under gravity

Consider the problem of a rigid body rotating in 3D space under gravity with one point fixed. I am particularly curious about the equilibrium state where the body is spinning at a constant angular ...
Zhang Yuhan's user avatar
1 vote
0 answers
41 views

The boundedness of dynamical systems discretized from Hamiltonian systems

Let $H(p,q) = T(q) + U(p)$ be a Hamiltonian function that defines a Hamiltonian system, i.e., \begin{align} &\frac{dp}{dt} = \frac{\partial H}{\partial q}(p,q) = \frac{dT}{dq},\\ &\frac{dq}{dt}...
Yi_Feng's user avatar
  • 47
1 vote
0 answers
77 views

What exactly are the benefits of keeping a Hamiltonian system of equations Hamiltonian during solving or transformation?

When faced with a system of differential equations that happens to be Hamiltonian in form, or a perturbation of a Hamiltonian system, we often see in classical work a clear attempt to pursue solutions ...
user135626's user avatar
1 vote
0 answers
67 views

Reduced master equation for a multistable Hamiltonian dynamical system

I am looking for rigorous results on the derivation of a reduced master equation for a (possibly stochastic) Hamiltonian dynamical system with a coercive potential energy term with multiple local ...
Arnold Neumaier's user avatar
1 vote
0 answers
65 views

Id monodromy in hamiltonian dynamics

In my problem I have non autonomous Hamiltonian which depends on 2 parameters (pretty close to oscillator Hamiltonian, $(a+b\cos t +1) p^2+(a+b\cos t-1)q^2$, $a,b$ - parameters). From numerical ...
cptpwnage's user avatar
0 votes
1 answer
214 views

Hamilton equations-Symplectic scheme [closed]

We know that $\dot{q} = \frac{\partial H}{\partial p}$ and $\dot{p} = -\frac{\partial H}{\partial q}$, and we also know the values $Q$ and $P$ respectively of $q$ and $p$ at a later time step $\Delta ...
Jokerp's user avatar
  • 111
0 votes
0 answers
90 views

Numerical detection of Cantori

It is known that as parameters vary in Hamiltonian system, KAM tori can break [1,2]. How to construct numerically the breaking tori? The most relevant paper that I could find is [3,4]. But it uses ...
0x11111's user avatar
  • 593
0 votes
0 answers
94 views

On the measure of regular and chaotic regions in a phase space

Consider a Hamiltonian, non-linear, dynamical system associated to $H(\vec{q},\vec{p})$. Assume that the number of effective degrees of freedom is relatively small, say $D=3,4,5$. Now choose a certain ...
AndreaPaco's user avatar