Integrable Geodesic Flows Research Articles

Integrable geodesic flow in 3D and webs of maximal rank

Integrable geodesic flow in 3D and webs of maximal rank

Integrable geodesic flows and metrisable second-order ordinary differential equations

It is well known that the system of ordinary differential equations (ODEs) describing geodesic flows of some Riemannian metrics on 2-surfaces admits a projection on a special class of second-order ODEs. In this paper we study in detail this special class of ODEs. We classify all such autonomous ODEs possessing autonomous first integrals that are fractional-quadratic in the first derivative. We construct all the families of integrable geodesic flows related to the ODEs under study. These families are parameterized by two arbitrary functions and contain metrics with superintegrable geodesic flows. We also study the inverse problem and find novel families of second-order ODEs that are related to integrable geodesic flows. We explicitly present first integrals of such ODEs. We find the general structure of metrisable second-order ODEs related to conformal metrics.

Orbital invariants of billiards and linearly integrable geodesic flows

Обнаружены и вычисляются траекторные инварианты интегрируемых топологических биллиардов с двумя степенями свободы при условии постоянства энергии системы. Инварианты (векторы вращения) вычисляются через функции вращения на однопараметрических семействах $2$-торов Лиувилля. Доказан аналог теоремы Лиувилля в окрестности регулярных слоев для кусочно гладких биллиардов. Введены переменные действие-угол. Получена общая формула для функций вращения. Гипотеза А. Т. Фоменко предполагала, что функции вращения топологических биллиардов монотонны. Для многих важных систем гипотеза подтвердилась, но обнаружились интересные биллиарды с немонотонными функциями вращения. В частности, вычислены траекторные инварианты биллиардов-книжек, реализующих (с точностью до лиувиллевой эквивалентности) линейно интегрируемые геодезические потоки двумерных поверхностей. При надлежащем изменении параметров потоков эти функции вращения становятся монотонными. Библиография: 45 названий.

New examples of non-polynomial integrals of two-dimensional geodesic flows *

In this paper, we continue to study integrable geodesic flows on 2-surfaces with non-polynomial first integrals which we started earlier in our previous papers. We construct explicitly new local examples of Riemannian metrics and such integrals via various approaches and methods such as the classical and the generalized hodograph methods, the method of separation of variables and some others.

On Some Properties of Semi-Hamiltonian Systems Arising in the Problem of Integrable Geodesic Flows on the Two-Dimensional Torus

On Some Properties of Semi-Hamiltonian Systems Arising in the Problem of Integrable Geodesic Flows on the Two-Dimensional Torus

Conformal geodesics on gravitational instantons

AbstractWe study the integrability of the conformal geodesic flow (also known as the conformal circle flow) on the SO(3)–invariant gravitational instantons. On a hyper–Kähler four–manifold the conformal geodesic equations reduce to geodesic equations of a charged particle moving in a constant self–dual magnetic field. In the case of the anti–self–dual Taub NUT instanton we integrate these equations completely by separating the Hamilton–Jacobi equations, and finding a commuting set of first integrals. This gives the first example of an integrable conformal geodesic flow on a four–manifold which is not a symmetric space. In the case of the Eguchi–Hanson we find all conformal geodesics which lie on the three–dimensional orbits of the isometry group. In the non–hyper–Kähler case of the Fubini–Study metric on $\mathbb{CP}^2$ we use the first integrals arising from the conformal Killing–Yano tensors to recover the known complete integrability of conformal geodesics.

The geodesic flow on nilmanifolds associated to graphs

We study the geodesic flow on nilmanifolds associated to graphs. We are interested in the construction of first integrals to show complete integrability on some compact quotients. We start on the corresponding Lie group equipped with a left-invariant metric, which is induced to the quotients. Also examples of integrable geodesic flows and of non-integrable ones are shown.

Integrable geodesic flows on orientable two-dimensional surfaces and topological billiards

The authors have recently introduced the class of topological billiards. Topological billiards are glued from elementary planar billiard sheets (bounded by arcs of confocal quadrics) along intervals of their boundaries. It turns out that the integrability of the elementary billiards implies that of the topological billiards. We show that all classical linearly and quadratically integrable geodesic flows on tori and spheres are Liouville equivalent to appropriate topological billiards. Moreover, the linear and quadratic integrals of the geodesic flows reduce to a single canonical linear integral and a single canonical quadratic integral on the billiard. These results are obtained within the framework of the Fomenko–Zieschang theory of the classification of integrable systems.

Circle problem and the spectrum of the Laplace operator on closed 2-manifolds

In this survey the circle problem is treated in the broad sense, as the problem of the asymptotic properties of the quantity , the remainder term in the circle problem. A survey of recent results in this direction is presented. The main focus is on the behaviour of on short intervals. Several conjectures on the local behaviour of which lead to a solution of the circle problem are presented. A strong universality conjecture is stated which links the behaviour of with the behaviour of the second term in Weyl’s formula for the Laplace operator on a closed Riemannian 2-manifold with integrable geodesic flow. Bibliography: 43 titles.

On exact solutions of a system of quasi-linear equations describing integrable geodesic flows on a surface

On exact solutions of a system of quasi-linear equations describing integrable geodesic flows on a surface

Asymptotic Eigenfunctions of the Operator ∇D(x)∇ Defined in a Two-Dimensional Domain and Degenerating on Its Boundary and Billiards with Semi-Rigid Walls

We propose a method for constructing asymptotic eigenfunctions of the operator L = ∇D(x1,x2)∇ defined in a domain Ω ? R 2 with coefficient D(x) degenerating on the boundary ∂Ω. Such operators arise, for example, in problems about long water waves trapped by coasts and islands. These eigenfunctions are associated with analogs of Liouville tori of integrable geodesic flows with the metric defined by the Hamiltonian system with Hamiltonian D(x)p2 and degenerating on ∂ Ω. The situation is unusual compared, say, with the case of integrable two-dimensional billiards, because the momentum components of trajectories on such “tori” are infinite over the boundary, where D(x) = 0, although their projections onto the plane R2 are compact sets, as a rule, diffeomorphic to annuli in R2. We refer to such systems as billiards with semi-rigid walls.

Integrable geodesic flows on orientable two-dimensional surfaces and topological billiards

Недавно авторами был введен класс топологических биллиардов. Топологические биллиарды получаются склейками элементарных плоских биллиардов-листов, ограниченных дугами софокусных квадрик, вдоль сегментов их границ. Интегрируемость элементарных биллиардов, оказывается, влечет интегрируемость топологических биллиардов. В статье доказывается, что классические линейно и квадратично интегрируемые геодезические потоки на торе и сфере лиувиллево эквиваленты подходящим топологическим биллиардам. При этом линейные и квадратичные интегралы геодезических потоков сводятся к одному каноническому линейному интегралу и к одному каноническому квадратичному интегралу на биллиарде. Эти результаты получены в рамках теории Фоменко-Цишанга классификации интегрируемых систем. Библиография: 64 наименования.

Liouville classification of integrable geodesic flows in a potential field on two-dimensional manifolds of revolution: the torus and the Klein bottle

We study integrable geodesic flows on surfaces of revolution (the torus and the Klein bottle). We obtain a Liouville classification of integrable geodesic flows on the surfaces under consideration with potential in the case of a linear integral. Here, the potential is invariant under an isometric action of the circle on the manifold of revolution. This classification is obtained on the basis of calculating the Fomenko-Zieschang invariants (marked molecules) of the systems. Bibliography: 18 titles.

On the complete integrability of the geodesic flow of pseudo-H-type Lie groups

Pseudo-H-type groups $$G_{r,s}$$ form a class of step-two nilpotent Lie groups with a natural pseudo-Riemannian metric. In this paper the question of complete integrability in the sense of Liouville is studied for the corresponding (pseudo-)Riemannian geodesic flow. Via the isometry group of $$G_{r,s}$$ families of first integrals are constructed. A modification of these functions gives a set of $$\dim G_{r,s}$$ functionally independent smooth first integrals in involution. The existence of a lattice L in $$G_{r,s}$$ is guaranteed by recent work of K. Furutani and I. Markina. The complete integrability of the pseudo-Riemannian geodesic flow of the compact nilmanifold $$L \backslash G_{r,s}$$ is proved under additional assumptions on the group $$G_{r,s}$$ .

Dissipative prolongations of the multipeakon solutions to the Camassa–Holm equation

Multipeakons are special solutions to the Camassa–Holm equation. They are described by an integrable geodesic flow on a Riemannian manifold. We present a bi-Hamiltonian formulation of the system explicitly and write down formulae for the associated first integrals. Then we exploit the first integrals and present a novel approach to the problem of the dissipative prolongations of multipeakons after the collision time. We prove that an n-peakon after a collision becomes an n−1-peakon for which the momentum is preserved.

Integrable geodesic flows on tubular sub-manifolds

In this paper we construct a new class of surfaces whose geodesic flow is integrable (in the sense of Liouville). We do so by generalizing the notion of tubes about curves to 3-dimensional manifolds, and using Jacobi fields we derive conditions under which the metric of the generalized tubular sub-manifold admits an ignorable coordinate. Some examples are given, demonstrating that these special surfaces can be quite elaborate and varied.

Topological classification of integrable geodesic flows in a potential field on the torus of revolution

A Liouville classification of integrable Hamiltonian systems which are the geodesic flows on 2-dimensional torus of revolution in a invariant potential field in the case of linear integral is obtained. This classification is obtained using the Fomenko–Zieschang invariant (marked molecules) of investigated systems. All types of bifurcation curves are described. Also a classification of singularities of the system solutions is obtained.

On a Certain Sub-Riemannian Geodesic Flow on the Heisenberg Group

Under study is an integrable geodesic flow of a left-invariant sub-Riemannian metric for a right-invariant distribution on the Heisenberg group. We obtain the classification of the trajectories of this flow. There are a few examples of trajectories in the paper which correspond to various values of the first integrals. These trajectories are obtained by numerical integration of the Hamiltonian equations. It is shown that for some values of the first integrals we can obtain explicit formulae for geodesics by inverting the corresponding Legendre elliptic integrals.

Liouville classification of integrable geodesic flows on a torus of revolution in a potential field

A Liouville classification of integrable Hamiltonian systems being geodesic flows on a twodimensional torus of revolution in an invariant potential field is obtained in the case of linear integral. This classification is obtained using the Fomenko–Zieschang invariant (so called marked molecules) of the systems under consideration. All types of bifurcation curves are described. A classification of singularities of the system solutions is also obtained.

On local description of two-dimensional geodesic flows with a polynomial first integral**dedicated to the 55th birthday of our friend E V Ferapontov.

In this paper we present a construction of multiparametric families of two-dimensional metrics with a polynomial first integral of arbitrary degree in momenta. Such integrable geodesic flows are described by solutions of some semi-Hamiltonian hydrodynamic-type system. We give a constructive algorithm for the solution of the derived hydrodynamic-type system, i.e. we found infinitely many conservation laws and commuting flows. Thus we were able to find infinitely many particular solutions of this hydrodynamic-type system by the generalized hodograph method. Therefore infinitely many particular two-dimensional metrics equipped with first integrals polynomial in momenta were constructed.