2,886,099 research outputs found
Quasiattractors in coupled maps and coupled dielectric cavities
We study the origin of attracting phenomena in the ray dynamics of coupled
optical microcavities. To this end we investigate a combined map that is
composed of standard and linear map, and a selection rule that defines when
which map has to be used. We find that this system shows attracting dynamics,
leading exactly to a quasiattractor, due to collapse of phase space. For
coupled dielectric disks, we derive the corresponding mapping based on a ray
model with deterministic selection rule and study the quasiattractor obtained
from it. We also discuss a generalized Poincar\'e surface of section at
dielectric interfaces.Comment: 7 pages, 7 figure
Invertible coupled KdV and coupled Harry Dym hierarchies
In this paper we discuss the conditions under which the coupled KdV and
coupled Harry Dym hierarchies possess inverse (negative) parts. We further
investigate the structure of nonlocal parts of tensor invariants of these
hierarchies, in particular, the nonlocal terms of vector fields, conserved
one-forms, recursion operators, Poisson and symplectic operators. We show that
the invertible cKdV hierarchies possess Poisson structures that are at most
weakly nonlocal while coupled Harry Dym hierarchies have Poisson structures
with nonlocalities of the third order
Coupled electric and magnetic dipole formulation for planar arrays of dipolar particles: metasurfaces with various electric and/or magnetic meta-atoms per unit cell
The optical properties of infinite planar array of scattering particles,
metasurfaces and metagratings, are attracting special attention lately for
their rich phenomenology, including both plasmonic and high-refractive-index
dielectric meta-atoms with a variety of electric and magnetic resonant
responses. Herein we derive a coupled electric and magnetic dipole (CEMD)
analytical formulation to describe the reflection and transmission of such
periodic arrays, including specular and diffractive orders, valid in the
spectral regimes where only dipolar multipoles are needed. Electric and/or
magnetic dipoles with all three orientations arising in turn from a single or
various meta-atoms per unit cell are considered. The 2D lattice Green function
is rewritten in terms of a 1D (chain) version that fully converges and can be
easily calculated. Modes emerging as poles of such lattice Green function can
be extracted. This formulation can be applied to investigate a wealth of
plasmonic, all-dielectric, and hybrid metasurfaces/metagratings of interest
throughout the electromagnetic spectrum.Comment: 8 pages, 4 figure
Coupled numerical multiphysics simulation methods in induction surface hardening
Numerical simulation is a valuable tool to help investigate complex multiphysics problems of engineering and science. This also applies to inductive surface hardening with its coupled electromagnetic and temperature fields as well as the microstructure changes of the hardened material. In this field, numerical simulation is a well-established approach for effective process design. This is particularly true since an analytical approach usually fails because of the complexity of the problems. Also, experiments oftentimes are not leading to a solution in an acceptable period of time because of the big number of process parameters. Furthermore, numerical simulation can help to investigate effects that could not have been observed otherwise. An example is the Joule heat distribution within a heated work piece during inductive heating. However, the fields of application as well as the methods of numerical simulation have to keep pace with technological progress. Two examples of new applications and methods for numerical simulation in induction hardening are presented in this paper: A complex 3D model of a large bearing and a new approach for the numerical simulation of the martensite microstructure
Strongly Coupled Inflaton
We continue to investigate properties of the strongly coupled inflaton in a
setup introduced in arXiv:0807.3191 through the AdS/CFT correspondence. These
properties are qualitatively different from those in conventional inflationary
models. For example, in slow-roll inflation, the inflaton velocity is not
determined by the shape of potential; the fine-tuning problem concerns the dual
infrared geometry instead of the potential; the non-Gaussianities such as the
local form can naturally become large.Comment: 12 pages; v3, minor revision, comments and reference added, JCAP
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