19 research outputs found
Non-holonomy, critical manifolds and stability in constrained Hamiltonian systems
We approach the analysis of dynamical and geometrical properties of
nonholonomic mechanical systems from the discussion of a more general class of
auxiliary constrained Hamiltonian systems. The latter is constructed in a
manner that it comprises the mechanical system as a dynamical subsystem, which
is confined to an invariant manifold. In certain aspects, the embedding system
can be more easily analyzed than the mechanical system. We discuss the geometry
and topology of the critical set of either system in the generic case, and
prove results closely related to the strong Morse-Bott, and Conley-Zehnder
inequalities. Furthermore, we consider qualitative issues about the stability
of motion in the vicinity of the critical set. Relations to sub-Riemannian
geometry are pointed out, and possible implications of our results for
engineering problems are sketched.Comment: Latex, 58 page
Art and handwork for the learning-handicapped child.
Thesis (Ed.M.)--Boston Universit
2D growth processes: SLE and Loewner chains
This review provides an introduction to two dimensional growth processes.
Although it covers a variety processes such as diffusion limited aggregation,
it is mostly devoted to a detailed presentation of stochastic Schramm-Loewner
evolutions (SLE) which are Markov processes describing interfaces in 2D
critical systems. It starts with an informal discussion, using numerical
simulations, of various examples of 2D growth processes and their connections
with statistical mechanics. SLE is then introduced and Schramm's argument
mapping conformally invariant interfaces to SLE is explained. A substantial
part of the review is devoted to reveal the deep connections between
statistical mechanics and processes, and more specifically to the present
context, between 2D critical systems and SLE. Some of the SLE remarkable
properties are explained, as well as the tools for computing with SLE. This
review has been written with the aim of filling the gap between the
mathematical and the physical literatures on the subject.Comment: A review on Stochastic Loewner evolutions for Physics Reports, 172
pages, low quality figures, better quality figures upon request to the
authors, comments welcom