662 research outputs found
The Poisson equations in the nonholonomic Suslov problem: Integrability, meromorphic and hypergeometric solutions
We consider the problem of integrability of the Poisson equations describing
spatial motion of a rigid body in the classical nonholonomic Suslov problem. We
obtain necessary conditions for their solutions to be meromorphic and show that
under some further restrictions these conditions are also sufficient. The
latter lead to a family of explicit meromorphic solutions, which correspond to
rather special motions of the body in space. We also give explicit extra
polynomial integrals in this case.
In the more general case (but under one restriction), the Poisson equations
are transformed into a generalized third order hypergeometric equation. A study
of its monodromy group allows us also to calculate the "scattering" angle: the
angle between the axes of limit permanent rotations of the body in space
Non-integrability of the problem of a rigid satellite in gravitational and magnetic fields
In this paper we analyse the integrability of a dynamical system describing
the rotational motion of a rigid satellite under the influence of gravitational
and magnetic fields. In our investigations we apply an extension of the Ziglin
theory developed by Morales-Ruiz and Ramis. We prove that for a symmetric
satellite the system does not admit an additional real meromorphic first
integral except for one case when the value of the induced magnetic moment
along the symmetry axis is related to the principal moments of inertia in a
special way.Comment: 39 pages, 4 figures, missing bibliography was adde
Non-integrability of the generalised spring-pendulum problem
We investigate a generalisation of the three dimensional spring-pendulum
system. The problem depends on two real parameters , where is the
Young modulus of the spring and describes the nonlinearity of elastic
forces. We show that this system is not integrable when . We
carefully investigated the case when the necessary condition for
integrability given by the Morales-Ramis theory is satisfied. We discuss an
application of the higher order variational equations for proving the
non-integrability in this case.Comment: 20 pages, 1 figur
Global integrability of cosmological scalar fields
We investigate the Liouvillian integrability of Hamiltonian systems
describing a universe filled with a scalar field (possibly complex). The tool
used is the differential Galois group approach, as introduced by Morales-Ruiz
and Ramis. The main result is that the generic systems with minimal coupling
are non-integrable, although there still exist some values of parameters for
which integrability remains undecided; the conformally coupled systems are only
integrable in four known cases. We also draw a connection with chaos present in
such cosmological models, and the issues of integrability restricted to the
real domain.Comment: This is a conflated version of arXiv:gr-qc/0612087 and
arXiv:gr-qc/0703031 with a new theory sectio
Integrability of planar polynomial differential systems through linear differential equations
In this work, we consider rational ordinary differential equations dy/dx =
Q(x,y)/P(x,y), with Q(x,y) and P(x,y) coprime polynomials with real
coefficients. We give a method to construct equations of this type for which a
first integral can be expressed from two independent solutions of a
second-order homogeneous linear differential equation. This first integral is,
in general, given by a non Liouvillian function. We show that all the known
families of quadratic systems with an irreducible invariant algebraic curve of
arbitrarily high degree and without a rational first integral can be
constructed by using this method. We also present a new example of this kind of
families. We give an analogous method for constructing rational equations but
by means of a linear differential equation of first order.Comment: 24 pages, no figure
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