16 research outputs found
Symmetries in Classical Field Theory
The multisymplectic description of Classical Field Theories is revisited,
including its relation with the presymplectic formalism on the space of Cauchy
data. Both descriptions allow us to give a complete scheme of classification of
infinitesimal symmetries, and to obtain the corresponding conservation laws.Comment: 70S05; 70H33; 55R10; 58A2
Dependent coordinates in path integral measure factorization
The transformation of the path integral measure under the reduction procedure
in the dynamical systems with a symmetry is considered. The investigation is
carried out in the case of the Wiener--type path integrals that are used for
description of the diffusion on a smooth compact Riemannian manifold with the
given free isometric action of the compact semisimple unimodular Lie group. The
transformation of the path integral, which factorizes the path integral
measure, is based on the application of the optimal nonlinear filtering
equation from the stochastic theory. The integral relation between the kernels
of the original and reduced semigroup are obtained.Comment: LaTeX2e, 28 page
Stochastic Differentiation - A Generalized Approach
The space (D*) of Wiener distributions allows a natural Pettis-type stochastic calculus. For a certain class of generalized multiparameter processes X: R N →(D*) we prove several differentiation rules (Itô formulas); these processes can be anticipating. We then apply these rules to some examples of square integrable Wiener functionals and look at the integral versions of the resulting formulas
Periodic orbits above the ecliptic plane in the solar sail restricted 3-body problem
We consider periodic orbits in the circular restricted three-body problem, where the third (small) body is a solar sail. In particular, we consider orbits about equilibrium points in the Earth-sun rotating frame, which are high above the ecliptic plane, in contrast to the classical "halo" orbits about the collinear equilibria. It is found that due to coupling in the equations of motion, periodic orbits about equilibria are naturally present at linear order. Using the method of Lindstedt-Poincaré, we construct nth order approximations to periodic solutions of the nonlinear equations of motion. It is found that there is much freedom in specifying the position and period/amplitude of the orbit of the sail, high above the ecliptic and looking down on the Earth.Aparticular use of such solutions is presented, namely, the year-round constant imaging of, and communication with, the poles. We find that these orbits present a significant improvement on the position of the sail when viewed from the Earth, compared to a sail placed at equilibrium
Endogenous entry in lowest-unique sealed-bid auctions
Sealed-bid auction, Evolutionary stability, Endogenous entry, Maximin, D44, C72, C73, C61, L83,