Search results for "DISPERSION"
showing 10 items of 1101 documents
Two-photon exchange contribution to elastic e− -proton scattering: Full dispersive treatment of πN states and comparison with data
2017
We evaluate the two-photon exchange correction to the elastic electron-proton scattering cross section within a dispersive framework. Besides the elastic contribution, we account for all $\ensuremath{\pi}N$ intermediate state contributions using the phenomenological MAID fit as an input. We develop a novel method for the analytical continuation of the two-photon exchange amplitudes into the unphysical region and generalize our previous work to the momentum transfer region $0.064\text{ }\text{ }{\mathrm{GeV}}^{2}\ensuremath{\lesssim}{Q}^{2}\ensuremath{\lesssim}1\text{ }\text{ }{\mathrm{GeV}}^{2}$. We compare our results with recent OLYMPUS, CLAS and VEPP-3 data as well as with empirical fits…
The coupling of the X1Σ+and a3Σ+states of the atom pair Na + Cs and modelling cold collisions
2006
The states X1?+ and a3?+ correlated to the ground-state asymptote of Na (3s) and Cs (6s) atoms have been experimentally investigated using high resolution Fourier-transform spectroscopy. The hyperfine splitting of the a3?+ state levels is partially resolved. Transitions to asymptotic vibrational levels of the a3?+ and X1?+ states were recorded simultaneously. The joint evaluation of the data of both the a3?+ and the X1?+ states allows us to determine accurate potential energy curves of both electronic states. Coupled-channels calculations are finally applied for deriving long range dispersion parameters and the exchange contribution of the molecular potentials, yielding a reliable descripti…
Reply to "Comment on 'Dispersion Interaction between Two Hydrogen Atoms in a Static Electric Field' "
2020
In their Comment on our Letter Dispersion Interaction between Two Hydrogen Atoms in a Static Electric Field, P. P. Abrantes et al. address one of the main points discussed in our Letter, that is, the possibility to manipulate interatomic interactions through an external static electric field. In our Letter, we have shown that the interaction between two ground-state atoms can be significantly modified, exploiting an external static electric field, and even turned from attractive to repulsive, depending on the strength of the external field and the geometrical configu- ration. In their Comment, Abrantes et al. point out that it is the electrostatic contribution between the electric dipoles i…
Stationary and Pulsating Dissipative Optical Bullets
2006
We demonstrate the existence of stable optical light bullets in nonlinear dissipative media. Beyond the domain where stable bullets are found, unstable bullets show unusual behaviors, like "optical rockets", pulsating solutions or pattern formation.
Switching dynamics of dark-pulse Kerr frequency comb states in optical microresonators
2021
Dissipative Kerr solitons are localized structures that exist in nonlinear optical cavities. They lead to the formation of microcombs - chip-scale frequency combs that could facilitate precision frequency synthesis and metrology by capitalizing on advances in silicon photonics. Previous demonstrations have mainly focused on anomalous dispersion cavities. Notwithstanding, localized structures also exist in the normal dispersion regime in the form of circulating dark pulses, but their physical dynamics is far from being understood. Here, we explore dark-pulse Kerr combs generated in normal dispersion optical microresonators and report the discovery of reversible switching between coherent dar…
Supercontinuum generation in silicon waveguides relying on wave-breaking
2015
Four-wave-mixing processes enabled during optical wave-breaking (OWB) are exploited in this paper for supercontinuum generation. Unlike conventional approaches based on OWB, phase-matching is achieved here for these nonlinear interactions, and, consequently, new frequency production becomes more efficient. We take advantage of this kind of pulse propagation to obtain numerically a coherent octave-spanning mid-infrared supercontinuum generation in a silicon waveguide pumping at telecom wavelengths in the normal dispersion regime. This scheme shows a feasible path to overcome limits imposed by two-photon absorption on spectral broadening in silicon waveguides.
Singlet ground state magnetism: III. magnetic excitons in antiferromagnetic TbP
1981
The dispersion of the lowest magnetic excitations of the singlet ground state system TbP has been studied in the antiferromagnetic phase by inelastic neutron scattering. The magnetic exchange interaction and the magnetic and the rhombohedral molecular fields have been determined.
Magnetic excitations of the singlet ground state antiferromagnet CsFeBr3 in a magnetic field
1991
Abstract The magnetic excitations in the quasi-one-dimensional singlet ground state antiferromagnet CsFeBr3 have been studied by inelastic neutron scattering in the presence of an applied magnetic field, H‖c and H⊥c. With H‖c, the dispersion curves renormalise so that the exchange interaction has a decreasing influence with increasing field. H⊥c has little or no effect on the dispersion of the magnetic excitations.
NGC1600 - Cluster or Field Elliptical?
2008
A study of the galaxy distribution in the field of the elliptical galaxy NGC1600 has been undertaken. Although this galaxy is often classified as a member of a loose group, all the neighbouring galaxies are much fainter and could be taken as satellites of NGC1600. The number density profile of galaxies in the field of this galaxy shows a decline with radius, with evidence of a background at approximately 1.3 Mpc. The density and number density profile are consistent with that found for other isolated early-type galaxies. NGC1600 appears as an extended source in X-rays, and the center of the X-ray emission seems not to coincide with the center of the galaxy. The velocity distribution of neig…
Generating ultra-short high-energy pulses using dissipative soliton resonance: Pulse compression schemes
2011
Dissipative soliton resonance (DSR) refers to a phenomenon where the energy of the stable soliton solution increases to extremely large values in a nonlinear dissipative system modeled by the complex cubic-quintic Ginzburg-Landau equation (CGLE) [1]. It occurs in the vicinity of a specific hyper-surface in the multi-dimensional space of the CGLE parameters. The phenomenon has applications in designing laser oscillators generating ultra-high energy pulses, since the dynamics of such lasers can be well-modeled by the CGLE. The DSR was first found in normally-dispersive media, in concordance with the current design trend for high-energy mode-locked laser oscillators [2–4]. However, we have sho…