Results 251 to 260 of about 927,050 (285)

Dirac bound states in the continuum in honeycomb photonic crystal slabs. [PDF]

Sci Rep
Chern RL, Kao YC, Hwang RR.
europepmc   +1 more source

Unidirectional Spectral Singularities [PDF]

Physical Review Letters, 2014
We propose a class of spectral singularities emerging from the coincidence of two independent singularities with highly directional responses. These spectral singularities result from resonance trapping induced by the interplay between parity-time ...
Yuan Wang, Xiang Zhang, Hamidreza Ramezani   +2 more
exaly   +5 more sources

On the concept of spectral singularities

Pramana - Journal of Physics, 2009
In this paper, we discuss the concept of spectral singularities for non-Hermitian Hamiltonians.
Gusein Sh Guseinov
exaly   +3 more sources

Semiclassical analysis of spectral singularities and their applications in optics

Physical Review A, 2011
Motivated by possible applications of spectral singularities in optics, we develop a semiclassical method of computing spectral singularities. We use this method to examine the spectral singularities of a planar slab gain medium whose gain coefficient ...
Ali Mostafazadeh
exaly   +7 more sources

Essential spectral singularities and the spectral expansion for the Hill operator

Communications on Pure and Applied Analysis, 2017
In this paper we investigate the spectral expansion for the one-dimensional Schrodinger operator with a periodic complex-valued potential. For this we consider in detail the spectral singularities and introduce new concepts as essential spectral singularities and singular quasimomenta.
O A Veliev
exaly   +6 more sources

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On the spectral singularities of watermarked audio

Proceedings Third International Conference on WEB Delivering of Music, 2004
To improve the robustness of watermarking, the spectral singularities resulting from the widely used noise-like author keystream are investigated with audio signals. Because such a keystream distributes its energy abruptly among all frequencies, either the Fourier spectrum or the wavelet spectrum of a watermarked version might become very rough and has
Xianfeng Zhao, Weinong Wang, Kefei Chen
openaire   +2 more sources

THEORY OF SINGULAR PERTURBATIONS IN THE CASE OF SPECTRAL SINGULARITIES OF THE LIMIT OPERATOR

Mathematics of the USSR-Sbornik, 1988
The authors consider the Cauchy problem in a Banach space for the differential equation \(\epsilon y'-A(t)y=h(t)\), t in (0,T), as \(\epsilon \to 0^+\) under the principal assumptions that (1) the operator A(t) has the spectral representation \(A(t)=\sum^{n}_{k=1}\lambda_ k(t)P_ k(t),\) t in [0,T], for projections \(P_ k\), and (2) the spectrum of A(t)
Eliseev, A. G., Lomov, S. A.
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Spectral measures with singularities

Acta Mathematica Hungarica, 1987
The author had proved in his paper [J. Oper. Theory 15, 307-325 (1986)] that for every closed operator T in a complex Banach space X there is a uniquely determined smallest closed subset of the extended spectrum \(\sigma\) (T) such that the reasonable kind of (generalized) spectral measure for T cannot be defined for the Borel subsets of this set.
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Spectral singularities of the nonhomogeneous Sturm-Liouville equations

Applied Mathematics Letters, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Murat Adivar, Elgiz Bairamov
exaly   +4 more sources