Search results for "Vector"
showing 10 items of 2660 documents
Flexible drift-compensation system for precise 3D force mapping in severe drift environments
2011
The acquisition of dense 3D data sets is of great importance, but also a challenge for scanning probe microscopy (SPM). Thermal drift often induces severe distortions in the data, which usually constrains the acquisition of dense data sets to experiments under ultra-high vacuum and low-temperature conditions. Atom tracking is an elegant approach to compensate for thermal drift and to position the microscope tip with highest precision. Here, we present a flexible drift compensation system which can easily be connected to existing SPM hardware. Furthermore, we describe a 3D data acquisition and position correction protocol, which is capable of handling large and non-linear drift as typically …
Shift-variant digital holographic microscopy: inaccuracies in quantitative phase imaging
2013
Inaccuracies introduced in quantitative phase digital holographic microscopy by the use of nontelecentric imaging systems are analyzed. Computer modeling of the experimental result shows that even negligible errors in the radius and center of curvature of the numerical compensation needed to get rid of the remaining quadratic phase factor introduce errors in the phase measurements; these errors depend on the position of the object in the field-of-view. However, when a telecentric imaging system is utilized for the recording of the holograms, the numerical modeling and experimental results show the shift-invariant behavior of the quantitative-phase digital holographic microscope.
Quantum algorithm for simulating an experiment: Light interference from single ions and their mirror images
2019
We widen the range of applications for quantum computing by introducing digital quantum simulation methods for coherent light-matter interactions: We simulate an experiment where the emitted light from a single ion was interfering with its mirror image [Eschner et al., Nature (London) 413, 495 (2001)]. Using the quantum simulation software q1tsim, we accurately reproduce the interference pattern which had been observed experimentally and also show the effect of the mirror position on the spontaneous-emission rate of the ion. In order to minimize the number of required qubits, we implement a qubit-reinitialization technique. We show that a digital quantum simulation of complex experiments in…
Role of Polarization Mode Dispersion on Modulational Instability in Optical Fibers
2001
We introduce the theory of modulational instability (MI) of electromagnetic waves in fibers with random polarization mode dispersion. Applying a linear stability analysis and stochastic calculus, we show that the MI gain spectrum reads as the maximal eigenvalue of a constant effective matrix. In the limiting cases of small or large fluctuations, we give explicit expressions for the MI gain spectra. In the general configurations, we give the explicit form of the effective matrix and numerically compute the maximal eigenvalue. In the anomalous dispersion regime, polarization dispersion widens the unstable bandwidth. Depending on the type of variations of the birefringence parameters, polariza…
E1 andE2/E0 form factors and strength distributions fromSi28(e,e’p) andSi28(e,e’α) coincidence scattering
1986
A model-independent multipole analysis of $^{28}\mathrm{Si}$(e,e'p) and $^{28}\mathrm{Si}$(e,e'\ensuremath{\alpha}) coincidence data, taken at three momentum transfers 0.39lql0.68 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$, yields both E1 and E2/E0 form factors and the respective multipole strength distributions in the giant-resonance region of $^{28}\mathrm{Si}$ (${E}_{x}$=14--22 MeV). While the deduced E1 strength agrees well with previous results, the total extracted E2/E0 strength is about twice the value found with isoscalar projectiles indicating the presence of large isovector E2/E0 contributions in the region of the isoscalar E2/E0 giant resonances.
Energy-exchange collision of the Manakov vector solitons under strong environmental perturbations
2007
International audience; We use a collective-variable approach to study the dynamical behavior of vector solitons in the Manakov system under strong environmental perturbations induced by the fiber losses and a modified cross-phase modulation parameter. We identify and discuss the salient features associated with energy-exchange collisions of transmissional and reflectional types. Particularly, we find that such perturbations can induce important effects not only on fundamental soliton parameters such as the peak power, central position, width, chirp, and frequency, but also on the nature of the collision. Interestingly, we find that the perturbations lead to only a slight alteration of coll…
Nonlinear Evolution Equations, Quasi-Solitons and their Experimental Manifestation
1990
We review the typical experimental facts which characterize quasisolitons in one-dimensional real systems, in connection with their modeling by nonlinear partial differential equations.We consider these nonlinear waves or excitations in two different domains of the real world : the macroworld and the microworld. In the macroworld we examine typical one-dimensional devices : the electrical networks, the Josephson transmission lines and the optical fibers, where the localized waves or pulses can be simply and coherently created, easily observed and manipulated on a macroscopic scale. In the microworld, we consider the magnetic chains and polymers, where the indirect experimental signatures of…
Efficient control of the energy exchange due to the Manakov vector-soliton collision
2003
By examining the concept of energy exchange among the orthogonally polarized components of each of two colliding (Manakov-like) vector solitons it is observed that a maximum or an efficient energy-exchange process is possible only for an appropriate choice of the initial physical parameters (namely, frequency separation, polarizations, time delay, and pulse-width separation between the colliding solitons) for which L(W) (walk-off length) >>L(NL) (nonlinear length). However, in this case only, the amount of energy-exchange can be considerably increased or decreased by appropriately changing the phases of colliding solitons without altering the walk-off length and the initial energy distribut…
Study of the $\bar K N$ system and coupled channels in a finite volume
2013
We investigate the $\bar KN$ and coupled channels system in a finite volume and study the properties of the $\Lambda(1405)$ resonance. We calculate the energy levels in a finite volume and solve the inverse problem of determining the resonance position in the infinite volume. We devise the best strategy of analysis to obtain the two poles of the $\Lambda(1405)$ in the infinite volume case, with sufficient precision to distinguish them.
Probing low-mass vector bosons with parity nonconservation and nuclear anapole moment measurements in atoms and molecules
2017
In the presence of P-violating interactions, the exchange of vector bosons between electrons and nucleons induces parity-nonconserving (PNC) effects in atoms and molecules, while the exchange of vector bosons between nucleons induces anapole moments of nuclei. We perform calculations of such vector-mediated PNC effects in Cs, Ba$^+$, Yb, Tl, Fr and Ra$^+$ using the same relativistic many-body approaches as in earlier calculations of standard-model PNC effects, but with the long-range operator of the weak interaction. We calculate nuclear anapole moments due to vector boson exchange using a simple nuclear model. From measured and predicted (within the standard model) values for the PNC ampli…