2,333 research outputs found
Opposite Thermodynamic Arrows of Time
A model in which two weakly coupled systems maintain opposite running
thermodynamic arrows of time is exhibited. Each experiences its own retarded
electromagnetic interaction and can be seen by the other. The possibility of
opposite-arrow systems at stellar distances is explored and a relation to dark
matter suggested.Comment: To appear in Phys. Rev. Let
Comment on “Surface Plasmons and Nonlocality: A Simple Model”
In the Comment [1], Schaich calculated the mode dispersion of surface plasmons supported by a planar metal-dielectric-metal (MIM) structure, and concluded that our model [2] fails to mimic the effect of nonlocality at high frequencies. Here, we shall clarify the difference between our calculations and that in Schaich’s Comment, and highlight the validity of our model for a general class of plasmonic structures.Published versio
Comparison of Stochastic Methods for the Variability Assessment of Technology Parameters
This paper provides and compares two alternative solutions for the simulation of cables and interconnects with the inclusion of the effects of parameter uncertainties, namely the Polynomial Chaos (PC) method and the Response Surface Modeling (RSM). The problem formulation applies to the telegraphers equations with stochastic coefficients. According to PC, the solution requires an expansion of the unknown parameters in terms of orthogonal polynomials of random variables. On the contrary, RSM is based on a least-square polynomial fitting of the system response. The proposed methods offer accuracy and improved efficiency in computing the parameter variability effects on system responses with respect to the conventional Monte Carlo approach. These approaches are validated by means of the application to the stochastic analysis of a commercial multiconductor flat cable. This analysis allows us to highlight the respective advantages and disadvantages of the presented method
Quantum noise and stochastic reduction
In standard nonrelativistic quantum mechanics the expectation of the energy
is a conserved quantity. It is possible to extend the dynamical law associated
with the evolution of a quantum state consistently to include a nonlinear
stochastic component, while respecting the conservation law. According to the
dynamics thus obtained, referred to as the energy-based stochastic Schrodinger
equation, an arbitrary initial state collapses spontaneously to one of the
energy eigenstates, thus describing the phenomenon of quantum state reduction.
In this article, two such models are investigated: one that achieves state
reduction in infinite time, and the other in finite time. The properties of the
associated energy expectation process and the energy variance process are
worked out in detail. By use of a novel application of a nonlinear filtering
method, closed-form solutions--algebraic in character and involving no
integration--are obtained for both these models. In each case, the solution is
expressed in terms of a random variable representing the terminal energy of the
system, and an independent noise process. With these solutions at hand it is
possible to simulate explicitly the dynamics of the quantum states of
complicated physical systems.Comment: 50 page
Transformation-optics description of nonlocal effects in plasmonic nanostructures
We develop an insightful transformation-optics approach to investigate the impact that nonlocality has on the optical properties of plasmonic nanostructures. The light-harvesting performance of a dimer of touching nanowires is studied by using the hydrodynamical Drude model, which reveals nonlocal resonances not predicted by previous local calculations. Our method clarifies the interplay between radiative and nonlocal effects in this nanoparticle configuration, which enables us to elucidate the optimum size that maximizes its absorption and field enhancement capabilitiesThis work was supported by the ESF plasmonbionanosense program, the Leverhulme Trust, and the Engineering and Physical Sciences Research Council (EPSRC
Educating professionals to support self-management in people with asthma or diabetes: protocol for a systematic review and scoping exercise
This report is independent research funded by the National Institute
for Health Research (Programme Development Grants, Implementing
supported asthma self-management in routine clinical care: designing,
refining, piloting and evaluating a whole systems implementation within an
MRC Phase IV programme of research, RP-DG-1213-10008). The views
expressed in this publication are those of the author(s) and not necessarily
those of the NHS, the National Institute for Health Research or the
Department of Health. This work is sponsored by the University of Edinburgh.
The funder and sponsor have not had any role in developing the protocol
Controlled Synchronization of One Class of Nonlinear Systems under Information Constraints
Output feedback controlled synchronization problems for a class of nonlinear
unstable systems under information constraints imposed by limited capacity of
the communication channel are analyzed. A binary time-varying coder-decoder
scheme is described and a theoretical analysis for multi-dimensional
master-slave systems represented in Lurie form (linear part plus nonlinearity
depending only on measurable outputs) is provided. An output feedback control
law is proposed based on the Passification Theorem. It is shown that the
synchronization error exponentially tends to zero for sufficiantly high
transmission rate (channel capacity). The results obtained for synchronization
problem can be extended to tracking problems in a straightforward manner, if
the reference signal is described by an {external} ({exogenious}) state space
model. The results are applied to controlled synchronization of two chaotic
Chua systems via a communication channel with limited capacity.Comment: 8 pages, 2 figure
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