Search results for "Persio"
showing 10 items of 1107 documents
Optical bullets and "rockets" in nonlinear dissipative systems and their transformations and interactions
2006
We demonstrate the existence of stable optical light bullets in nonlinear dissipative media for both cases of normal and anomalous chromatic dispersion. The prediction is based on direct numerical simulations of the (3+1)-dimensional complex cubic-quintic GinzburgLandau equation. We do not impose conditions of spherical or cylindrical symmetry. Regions of existence of stable bullets are determined in the parameter space. Beyond the domain of parameters where stable bullets are found, unstable bullets can be transformed into >rockets> i.e. bullets elongated in the temporal domain. A few examples of the interaction between two optical bullets are considered using spatial and temporal interact…
ETUDE ET RÉALISATION D'UN DETECTEUR (FILTRE) MULTISPECTRAL PAR DISPERSION NON DESTRUCTIVE SPECTRALE A TRAVERS DES FILMES A NONSTRUCTURE
2020
The development of multispectral imaging, holography and lithography techniques exploits the properties of diffracting arrays in a wide variety of photonic components. They are incorporated in laser diodes as distributed Bragg reflectors, in various integrated optical functions for wavelength division multiplexing or optical interconnections, or inscribed within the fibers themselves, leading to a wide variety of sensors for detection of chemical elements, measurement of temperatures, pressures, accelerations of acquisition and or restitution of multispectral images, etc. [Lee et al. 2007] [Pagnoux et al. 2005].Among these devices, the resonant networks arouse a great interest because they …
Two-photon exchange correction to2S−2Psplitting in muonicHe3ions
2017
We calculate the two-photon exchange correction to the Lamb shift in muonic $^{3}\mathrm{He}$ ions within the dispersion relations framework. Part of the effort entailed making analytic fits to the electron-$^{3}\mathrm{He}$ quasielastic scattering data set, for purposes of doing the dispersion integrals. Our result is that the energy of the $2S$ state is shifted downwards by two-photon exchange effects by 15.14(49) meV, in good accord with the result obtained from a potential model and effective field theory calculation.
Quantization of the elastic modes in an isotropic plate
2006
We quantize the elastic modes in a plate. For this, we find a complete, orthogonal set of eigenfunctions of the elastic equations and we normalize them. These are the phonon modes in the plate and their specific forms and dispersion relations are manifested in low temperature experiments in ultra-thin membranes.
High-Pressure Raman Study of Fe(IO3)3: Soft-Mode Behavior Driven by Coordination Changes of Iodine Atoms
2020
[EN] We report high-pressure Raman spectroscopy studies of Fe(IO3)(3) up to nearly 21 GPa that have been interpreted with the help of density functional theory calculations, which include the calculation of phonon dispersion curves and elastic constants at different pressures. Zero-pressure Raman-active mode frequencies and their pressure dependences have been determined. Modes have been assigned and correlated to atomic movements with the help of calculations. Interestingly, in the high-frequency region, there are several modes that soften under compression. These modes have been identified as internal vibrations of the IO3 coordination polyhedron. Their unusual behavior is a consequence o…
A dispersion theoretical approach to the threshold amplitudes of pion photoproduction
1996
We give predictions for the partial wave amplitudes of pion photoproduction near threshold by means of dispersion relations at fixed t. The free parameters of this approach are determined by a fit to experimental data in the energy range 160 MeV $\le E_{\gamma} \le$ 420 MeV. The observables near threshold are found to be rather sensitive to the amplitudes in the resonance region, in particular to the $\Delta$ (1232) and $N^*$ (1440). We obtain a good agreement with the existing threshold data for both charged and neutral pion production. Our predictions also agree well with the results of chiral perturbation theory, except for neutral pion production off the neutron.
Virtual Compton scattering and the generalized polarizabilities of the proton atQ2=0.92and 1.76 GeV2
2012
Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson Lab using the exclusive photon electroproduction reaction (e p --> e p gamma). This paper gives a detailed account of the analysis which has led to the determination of the structure functions P{sub LL}-P{sub TT}/epsilon and P{sub LT}, and the electric and magnetic generalized polarizabilities (GPs) alpha{sub E}(Q{sup 2}) and beta{sub M}(Q{sup 2}) at values of the four-momentum transfer squared Q{sup 2} = 0.92 and 1.76 GeV{sup 2}. These data, together with the results of VCS experiments at lower momenta, help building a coherent picture of the electric and magnetic GPs of the proton over the full measured Q{sup 2}-…
The real part of the elastic-scattering amplitude at the $$S\bar ppS$$ and predictions at LHC and SSCand predictions at LHC and SSC
1994
A precise measurement of\(\bar pp\) elastic scattering in the Coulomb strong-interaction interference region was performed at the CERN\(S\bar ppS\) Collider at a centre-of-mass energy of 541 GeV. The ratio of the real-to-imaginary part of the forward elastic-scattering amplitude was found to be ρ=0.135±0.015. The slope of the exponential fall-off of the strong-interaction part was also measured to beb=15.5±0.1 GeV−2. Using this new result, an overall fit to the data on the total cross-section and on the real part for\(\bar pp\) and pp was performed using dispersion relations. Numerical predictions are presented for total cross-sections at LHC and SSC energies.
Elastic properties of CsCN
1983
The temperature dependence of the elastic constants of CsCN exhibiting the CsCl structure was measured with ultrasonic and neutron techniques. The room temperature values were found to bec11=18.8,c12=10.7 andc44=2.95 1010 dyn/cm2. The sound waves inT2g andEg symmetries exhibit anomalous temperature effects which are similar but definitively weaker than those in the NaCl type cyanides. In addition we measured the acoustic phonon dispersion along [100] and [110]. These results are compared with recent molecular dynamics calculations.
Analytical design of 160 Gbits/s densely dispersion-managed optical fiber transmission systems using Gaussian and raised cosine RZ ansätze
2004
We present an easy and efficient analytical method to design 160 Gbits/s densely dispersion-managed optical fiber transmission systems using Gaussian and raised cosine RZ ansatze.