8,266 research outputs found
Free quasi-symmetric functions, product actions and quantum field theory of partitions
We examine two associative products over the ring of symmetric functions
related to the intransitive and Cartesian products of permutation groups. As an
application, we give an enumeration of some Feynman type diagrams arising in
Bender's QFT of partitions. We end by exploring possibilities to construct
noncommutative analogues.Comment: Submitted 28.11.0
Intrinsically localized chaos in discrete nonlinear extended systems
The phenomenon of intrinsic localization in discrete nonlinear extended
systems, i.e. the (generic) existence of discrete breathers, is shown to be not
restricted to periodic solutions but it also extends to more complex (chaotic)
dynamical behaviour. We illustrate this with two different forced and damped
systems exhibiting this type of solutions: In an anisotropic Josephson junction
ladder, we obtain intrinsically localized chaotic solutions by following
periodic rotobreather solutions through a cascade of period-doubling
bifurcations. In an array of forced and damped van der Pol oscillators, they
are obtained by numerical continuation (path-following) methods from the
uncoupled limit, where its existence is trivially ascertained, following the
ideas of the anticontinuum limit.Comment: 6 pages, 6 figures, to appear in Europhysics Letter
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