Search results for "Dispersion"

The X-ray Luminosity - Velocity Dispersion relation in the REFLEX Cluster Survey

2003

We present an estimate of the bolometric X-ray luminosity - velocity dispersion L_x - sigma_v relation measured from a new, large and homogeneous sample of 171 low redshift, X-ray selected galaxy clusters. The linear fitting of log(L_x) - log(sigma_v) gives L_x = 10^{32.72 \pm 0.08} sigma^{4.1 \pm 0.3}_v erg s^{-1} h^{-2}_{50}. Furthermore, a study of 54 clusters, for which the X-ray temperature of the intracluster medium T is available, allows us to explore two other scaling relations, L_x -T and sigma_v -T. From this sample we obtain L_x \propto T^{3.1 \pm 0.2} and sigma_v \propto T^{1.00 \pm 0.16}, which are fully consistent with the above result for the L_x-sigma_v. The slopes of L_x -T…

On the effect of damping on dispersion curves in plates

2013

AbstractThis paper presents a study on quantitative prediction and understanding of time-harmonic wave characteristics in damped plates. Material dissipation is modelled by using complex-valued velocities of free dilatation and shear waves in an unbounded volume. As a numerical example, solution of the classical Rayleigh–Lamb problem for a viscoelastic plate is presented to illustrate and discuss the role of dissipation in the cut-off phenomenon and in the phenomenon of veering for dispersion curves. These phenomena are explained in more detail considering a simple model, which allows accurate asymptotic analysis of the perturbation of dispersion curves in the regions of cut-off and veering.

Ground states of ultrasoft particles with attractions: a genetic algorithm approach

2009

International audience; We analyze in detail the ground-state structure of model systems of athermal star polymers with an additional, tunable attraction that may result from dispersion or depletion forces. To perform a free, unbiased search in the space spanned by the crystal parameters, we employ genetic algorithms, which are enhanced with respect to previous versions in their ability to find stable structures that occupy very narrow basins of attraction in the energy landscape. Application of this method brings about a very large variety of ground states for star polymers with attractions, in particular for the case of intermediate functionalities and strong, short-range attractive force…

Manakov Polarization Modulation Instability in Normal Dispersion Optical Fiber

2014

We observed polarization modulation instability in the normal dispersion regime of randomly birefringent multi-km telecom optical fiber. The instability is pumped by two wavelength multiplexed and orthogonally polarized intense continuous lasers.

Optical Bistability and Switching in Oppositely Directed Coupler

2016

We report the optical bistability in two core oppositely directed coupler with negative index material channel. Using Langrangian variational method and Jacobi elliptic functions, we construct the solutions of the coupled nonlinear Schrodinger equations. The bistability arises due to the effective feedback mechanism as a result of opposite directionality of the phase velocity and energy flow in the negative index material channel. We report the various ways to control and manipulate the bistability threshold and hysteresis loop, which could be useful in the design and development of fast and low-threshold optical switches.

A dispersion relation for the pion-mass dependence of hadron properties

2010

We present a dispersion relation in the pion-mass squared, which static quantities (nucleon mass, magnetic moment, etc.) obey under the assumption of analyticity in the entire complex $m_\pi^2$ plane modulo a cut at negative $m_\pi^2$ associated with pion production. The relation is verified here in a number of examples of nucleon and $\Delta$-isobar properties computed in chiral perturbation theory up to order $p^3$. We outline a method to obtain relations for other mass-dependencies, and illustrate it on a two-loop example.

Inelastic scattering and interactions of three-wave parametric solitons.

2006

We study the interactions of velocity-locked three-wave parametric solitons in a medium with quadratic nonlinearity and dispersion. We reveal that the inelastic scattering between three-wave solitons and linear waves may be described in terms of analytical solutions with dynamically varying group velocity, or boomerons. Moreover, we demonstrate the elastic nature of three-wave soliton-soliton collisions and interactions.

2018

In this manuscript, we experimentally and numerically investigate the chaotic dynamics of the state-of-polarization in a nonlinear optical fiber due to the cross-interaction between an incident signal and its intense backward replica generated at the fiber-end through an amplified reflective delayed loop. Thanks to the cross-polarization interaction between the two-delayed counter-propagating waves, the output polarization exhibits fast temporal chaotic dynamics, which enable a powerful scrambling process with moving speeds up to 600-krad/s. The performance of this all-optical scrambler was then evaluated on a 10-Gbit/s On/Off Keying telecom signal achieving an error-free transmission. We a…

Optical phonon modes of wurtzite InP

2013

Optical vibration modes of InP nanowires in the wurtzite phase were investigated by Raman scattering spectroscopy. The wires were grown along the [0001] axis by the vapor-liquid-solid method. The A1(TO), E2h, and E1(TO) phonon modes of the wurtzite symmetry were identified by using light linearly polarized along different directions in backscattering configuration. Additionally, forbidden longitudinal optical modes have also been observed. Furthermore, by applying an extended 11-parameter rigid-ion model, the complete dispersion relations of InP in the wurtzite phase have been calculated, showing a good agreement with the Raman experimental data.

The band structure of double excited states for a linear chain

2000

Abstract The energy band structure in the case of double excited states of finite spin systems (s= 1 2 ) has been investigated. A geometrical construction based on the Bethe Ansatz method for determining eigenstates has been proposed. The formula for energy spectrum in the center and at the border of Brillouin zone has been obtained. Classification of energy bands has been elaborated on and approximated dispersion law for bounded states given. Some problems with application of the Bethe Ansatz in the case of finite system has been pointed out.