3,422 research outputs found
A semiflexible polymer chain under geometrical restrictions: Only bulk behaviour and no surface adsorption
We analyse the conformational behaviour of a linear semiflexible homo-polymer
chain confined by two geometrical constraints under a good solvent condition in
two dimensions. The constraints are stair shaped impenetrable surfaces. The
impenetrable surfaces are lines in a two dimensional space. The infinitely long
polymer chain is confined in between such two (A and B) surfaces. A lattice
model of a fully directed self-avoiding walk is used to calculate the exact
expression of the partition function, when the chain has attractive interaction
with one or both the constraints. It has been found that under the proposed
model, the chain shows only a bulk behaviour. In other words, there is no
possibility of adsorption of the chain due to restrictions imposed on the walks
of the chain.Comment: 9 pages, 2 figure
Control of dynamical instability in semiconductor quantum nanostructures diode lasers: role of phase-amplitude coupling
We numerically investigate the complex nonlinear dynamics for two
independently coupled laser systems consisting of (i) mutually delay-coupled
edge emitting diode lasers and (ii) injection-locked quantum nano-structures
lasers. A comparative study in dependence on the dynamical role of alpha
parameter, which determine the phase-amplitude coupling of the optical field,
in both the cases is probed. The variation of alpha lead to conspicuous changes
in the dynamics of both the systems, which are characterized and investigated
as a function of optical injection strength for the fixed coupled-cavity delay
time. Our analysis is based on the observation that the cross-correlation and
bifurcation measures unveil the signature of enhancement of amplitude-death
islands in which the coupled lasers mutually stay in stable phase-locked
states. In addition, we provide a qualitative understanding of the physical
mechanisms underlying the observed dynamical behavior and its dependence on
alpha. The amplitude death and the existence of multiple amplitude death
islands could be implemented for applications including diode lasers
stabilization.Comment: 9 Pages. arXiv admin note: text overlap with arXiv:1111.2439 by other
author
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