3,826 research outputs found
A multiplicity result for double singularly perturbed elliptic systems
We show that the number of low energy solutions of a double singularly
perturbed Schroedinger Maxwell system type on a smooth 3 dimensional manifold
(M,g) depends on the topological properties of the manifold. The result is
obtained via Lusternik Schnirelmann category theory
The Role of Spin Anisotropy in the Unbinding of Interfaces
We study the ground state of a classical X-Y model with -fold spin
anisotropy in a uniform external field, . An interface is introduced
into the system by a suitable choice of boundary conditions. For large , as
, we prove using an expansion in that the interface unbinds
from the surface through an infinite series of layering transitions. Numerical
work shows that the transitions end in a sequence of critical end points.Comment: 7 pages RevTeX, plus 1 postscript figure available from the authors
OUTP-94-41
Topological jamming of spontaneously knotted polyelectrolyte chains driven through a nanopore
The advent of solid state nanodevices allows for interrogating the
physico-chemical properties of a polyelectrolyte chain by electrophoretically
driving it through a nanopore. Salient dynamical aspects of the translocation
process have been recently characterized by theoretical and computational
studies of model polymer chains free from self-entanglement. However,
sufficiently long equilibrated chains are necessarily knotted. The impact of
such topological "defects" on the translocation process is largely unexplored,
and is addressed in this study. By using Brownian dynamics simulations on a
coarse-grained polyelectrolyte model we show that knots, despite being trapped
at the pore entrance, do not "per se" cause the translocation process to jam.
Rather, knots introduce an effective friction that increases with the applied
force, and practically halts the translocation above a threshold force. The
predicted dynamical crossover, which is experimentally verifiable, is of
relevance in applicative contexts, such as DNA nanopore sequencing.Comment: 6 pages; 7 figure
Holographic field theory models of dark energy in interaction with dark matter
We discuss two lagrangian interacting dark energy models in the context of
the holographic principle. The potentials of the interacting fields are
constructed. The models are compared with CMB distance information, baryonic
acoustic oscilations, lookback time and the Constitution supernovae sample. For
both models the results are consistent with a non vanishing interaction between
dark sectors - with more than three standard deviations of confidence for one
of them. Moreover, in both cases, the sign of coupling is consistent with dark
energy decaying into dark matter, alleviating the coincidence problem.Comment: arXiv admin note: substantial text overlap with arXiv:0912.399
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