1,513 research outputs found
High-order harmonic generation from Rydberg states at fixed Keldysh parameter
Because the commonly adopted viewpoint that the Keldysh parameter
determines the dynamical regime in strong field physics has long been
demonstrated to be misleading, one can ask what happens as relevant physical
parameters, such as laser intensity and frequency, are varied while is
kept fixed. We present results from our one- and fully three-dimensional
quantum simulations of high-order harmonic generation (HHG) from various bound
states of hydrogen with up to 40, where the laser intensities and the
frequencies are scaled from those for in order to maintain a fixed
Keldysh parameter for all . We find that as we increase
while keeping fixed, the position of the cut-off scales in well
defined manner. Moreover, a secondary plateau forms with a new cut-off,
splitting the HHG plateau into two regions. First of these sub-plateaus is
composed of lower harmonics, and has a higher yield than the second one. The
latter extends up to the semiclassical cut-off. We find that this
structure is universal, and the HHG spectra look the same for all
when plotted as a function of the scaled harmonic order. We investigate the
-, - and momentum distributions to elucidate the physical mechanism
leading to this universal structure
Phase-dependent interference fringes in the wavelength scaling of harmonic efficiency
We describe phase-dependent wavelength scaling of high-order harmonic
generation efficiency driven by ultra-short laser fields in the mid-infrared.
We employ both numerical solution of the time-dependent Schr\"{o}dinger
equation and the Strong Field Approximation to analyze the fine-scale
oscillations in the harmonic yield in the context of channel-closing effects.
We show, by varying the carrier-envelope phase, that the amplitude of these
oscillations depend strongly on the number of returning electron trajectories.
Furthermore, the peak positions of the oscillations vary significantly as a
function of the carrier-envelope phase. Owing to its practical applications, we
also study the wavelength dependence of harmonic yield in the "single-cycle"
limit, and observe a smooth variation in the wavelength scaling originating
from the vanishing fine-scale oscillations.Comment: 5 pages, 4 figure
A local version of the Pawlucki-Plesniak extension operator
Cataloged from PDF version of article.Using local interpolation of Whitney functions, we generalize the Pawłucki and Pleśniak approach to construct a continuous linear extension operator. We show the continuity of the modified operator in the case of generalized Cantor-type sets without Markov's Property. © 2004 Elsevier Inc. All rights reserved
Dielectronic Recombination of Fe XV forming Fe XIV: Laboratory Measurements and Theoretical Calculations
We have measured resonance strengths and energies for dielectronic
recombination (DR) of Mg-like Fe XV forming Al-like Fe XIV via N=3 -> N' = 3
core excitations in the electron-ion collision energy range 0-45 eV. All
measurements were carried out using the heavy-ion Test Storage Ring at the Max
Planck Institute for Nuclear Physics in Heidelberg, Germany. We have also
carried out new multiconfiguration Breit-Pauli (MCBP) calculations using the
AUTOSTRUCTURE code. For electron-ion collision energies < 25 eV we find poor
agreement between our experimental and theoretical resonance energies and
strengths. From 25 to 42 eV we find good agreement between the two for
resonance energies. But in this energy range the theoretical resonance
strengths are ~ 31% larger than the experimental results. This is larger than
our estimated total experimental uncertainty in this energy range of +/- 26%
(at a 90% confidence level). Above 42 eV the difference in the shape between
the calculated and measured 3s3p(^1P_1)nl DR series limit we attribute partly
to the nl dependence of the detection probabilities of high Rydberg states in
the experiment. We have used our measurements, supplemented by our
AUTOSTRUCTURE calculations, to produce a Maxwellian-averaged 3 -> 3 DR rate
coefficient for Fe XV forming Fe XIV. The resulting rate coefficient is
estimated to be accurate to better than +/- 29% (at a 90% confidence level) for
k_BT_e > 1 eV. At temperatures of k_BT_e ~ 2.5-15 eV, where Fe XV is predicted
to form in photoionized plasmas, significant discrepancies are found between
our experimentally-derived rate coefficient and previously published
theoretical results. Our new MCBP plasma rate coefficient is 19-28% smaller
than our experimental results over this temperature range
A fixed point theorem for multi-maps satisfying an implicit relation on metrically convex metric spaces
In this paper, we give a fixed point theorem for multi-valued mapping
satisfying an implicit relation on metrically convex metric spaces. This
result extends and generalizes some fixed point theorem in the literature
Improved chemotaxis differential evolution optimization algorithm
The social foraging behavior of Escherichia coli has recently received great attention and it has been employed to solve complex search optimization problems.This paper presents a modified bacterial foraging optimization BFO algorithm, ICDEOA (Improved Chemotaxis Differential Evolution Optimization Algorithm), to cope with premature convergence of reproduction operator.In ICDEOA, reproduction operator of BFOA is replaced with probabilistic reposition operator to enhance the intensification and the diversification of the search space.ICDEOA was compared with state-of-the-art DE and non-DE variants on 7 numerical functions of the 2014 Congress on Evolutionary Computation (CEC 2014). Simulation results
of CEC 2014 benchmark functions reveal that ICDEOA performs better than that of competitors in terms of the quality of the final solution for high dimensional problems
Analog neural network based on memristor crossbar arrays
In this paper, a new feed forward analog neural network is designed using a memristor based crossbar array architecture. This structure consists of positive and negative polarity connection matrices. In order to show the performance and usefulness of the proposed circuit, it is
considered a sample application of iris data recognition. The proposed neural network implementation is approved by the simulation in Cadence design environment using 0.35µm CMOS technology. The results obtained are promising for the implementation of high density neural network.This work is part of a project that has received funding from the European Union’s H2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement #69117
Immunization of Rainbow Trout (Oncorhynchus mykiss) against Lactococcus garvieae Using Vaccine Mixtures
The effectiveness of vaccine mixtures against lactococcosis was tested in rainbow trout (Oncorhynchus mykiss). The M1 strain of Lactococcus garvieae, isolated from a recent outbreak of lactococcosis at a rainbow trout farm in Turkey, was used in a trial comparing five immuniza- tion treatments: (a) formalin inactivated bacterin (vaccine), (b) the above bacterin together with Freund’s Incomplete Adjuvant (FIA), (c) the bacterin combined with β-glucan, (d) β-glucan only, and (e) phosphate buffered saline-PBS (control). Fish were given intrapritoneal injections and challenged by exposure to the bacteria 30, 75, or 125 days after vaccination. In fish exposed to the bacteria 30 days after injection, the relative percent survival (RPS) was 88.89% in the group that received only bacterin and 100% in the group that received the bacterin combined with FIA. Immunity remained high in the bacterin+FIA group, as the RPS in this group remained 100% in fish challenged at 75 days, significantly higher than in all other groups. In fish exposed to the bacteria 125 days after vaccination, the RPS was 54.55% in fish vaccinated with the bacterin only and 84.84% in fish vaccinated with bacterin+FIA. In the group that received only β-glucan, immunity did not improve after vaccination. Micro-agglutination tests of serums showed that immunized fish produced antibodies at high titers within 30 days. In short, the formalin-inacti- vated M1 strain provided longer lasting protection against Lactococcus garvieae in rainbow trout when combined with FIA than when administered alone or with β-glucan
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