271 research outputs found
Long-range Energy Transfer and Ionization in Extended Quantum Systems Driven by Ultrashort Spatially Shaped Laser Pulses
The processes of ionization and energy transfer in a quantum system composed
of two distant H atoms with an initial internuclear separation of 100 atomic
units (5.29 nm) have been studied by the numerical solution of the
time-dependent Schr\"odinger equation beyond the Born-Oppenheimer
approximation. Thereby it has been assumed that only one of the two H atoms was
excited by temporally and spatially shaped laser pulses at various laser
carrier frequencies. The quantum dynamics of the extended H-H system, which was
taken to be initially either in an unentangled or an entangled ground state,
has been explored within a linear three-dimensional model, including two z
coordinates of the electrons and the internuclear distance R. An efficient
energy transfer from the laser-excited H atom (atom A) to the other H atom
(atom B) and the ionization of the latter have been found. It has been shown
that the physical mechanisms of the energy transfer as well as of the
ionization of atom B are the Coulomb attraction of the laser driven electron of
atom A by the proton of atom B and a short-range Coulomb repulsion of the two
electrons when their wave functions strongly overlap in the domain of atom B.Comment: 11 pages, 7 figure
Intensive Wheat Management for Yield and Quality: The Role of Variety, Environment, and Management Practices
Management (M), variety (V), and environment (E) greatly influence wheat yield and quality. With the objective of determining the partial influence of V, E, and M, we conducted a field experiment where we imposed four management intensities to five wheat varieties during six site-years in Kansas and Oklahoma. Management intensities were 1) low-input (N fertility for a yield goal of 60 bu/a); 2) high-input (foliar fungicide, sulfur and chloride fertilizers, growth regulator, and nitrogen (N) fertility for a yield goal of 100 bu/a); 3) high-input minus fungicide; and 4) high-input minus additional N. We selected commonly grown wheat varieties with contrasting yield potential and quality characteristics. We used a split-plot design with M as whole-plots (established in randomized complete block design), and V as sub-plot (completely randomized within whole-plot). Variance component analyses suggested that E accounted for 63% of the variability in wheat yield and 55% of the variability in grain test weight; G accounted for 1 and 23% of the variability in yield and test weight, and M accounted for 1% of the variability of both. The interactions V × G and E × M accounted for 4 and 9% of the variability in yield, and 10 and 1% of the variability in test weight, respectively. Analysis of variance pooled across the entire dataset considering V and M fixed and E random suggested a significant G × M interaction on yield, which ranged from 49–61 bu/a. Meanwhile, both V and M affected test weight, which ranged from 52–58 lb/bu for the different V and from 55–57 lb/bu for the different M. These results suggest that E has the greatest impact in yield and quality, but there is room for yield improvement through V-specific M, and for quality improvement through V and M separately
A new regime of anomalous penetration of relativistically strong laser radiation into an overdense plasma
It is shown that penetration of relativistically intense laser light into an
overdense plasma, accessible by self-induced transparency, occurs over a finite
length only. The penetration length depends crucially on the overdense plasma
parameter and increases with increasing incident intensity after exceeding the
threshold for self-induced transparency. Exact analytical solutions describing
the plasma-field distributions are presented.Comment: 6 pages, 2 figures in 2 separate eps files; submitted to JETP Letter
Multi-filament structures in relativistic self-focusing
A simple model is derived to prove the multi-filament structure of
relativistic self-focusing with ultra-intense lasers. Exact analytical
solutions describing the transverse structure of waveguide channels with
electron cavitation, for which both the relativistic and ponderomotive
nonlinearities are taken into account, are presented.Comment: 21 pages, 12 figures, submitted to Physical Review
Incorporating lessons from high-input research into a low-margin year
Increased soybean commodity prices in recent years have generated interest in developing high-input systems to increase yield. However, little information exists about the effects of input-intensive, high-yield management on soybean yield and profitability, as well as interactions with basic agronomic practices
Stability of narrow beams in bulk Kerr-type nonlinear media
We consider (2+1)-dimensional beams, whose transverse size may be comparable
to or smaller than the carrier wavelength, on the basis of an extended version
of the nonlinear Schr\"{o}dinger equation derived from the Maxwell`s equations.
As this equation is very cumbersome, we also study, in parallel to it, its
simplified version which keeps the most essential term: the term which accounts
for the {\it nonlinear diffraction}. The full equation additionally includes
terms generated by a deviation from the paraxial approximation and by a
longitudinal electric-field component in the beam. Solitary-wave stationary
solutions to both the full and simplified equations are found, treating the
terms which modify the nonlinear Schr\"{o}dinger equation as perturbations.
Within the framework of the perturbative approach, a conserved power of the
beam is obtained in an explicit form. It is found that the nonlinear
diffraction affects stationary beams much stronger than nonparaxiality and
longitudinal field. Stability of the beams is directly tested by simulating the
simplified equation, with initial configurations taken as predicted by the
perturbation theory. The numerically generated solitary beams are always stable
and never start to collapse, although they display periodic internal
vibrations, whose amplitude decreases with the increase of the beam power.Comment: 7 pages, 6 figures Accepted for publication in PR
Bilateral symmetry breaking in a nonlinear Fabry-Perot cavity exhibiting optical tristability
We show the existence of a region in the parameter space that defines the
field dynamics in a Fabry-Perot cylindrical cavity, where three output stable
stationary states of the light are possible for a given localized incident
field. Two of these states do not preserve the bilateral (i.e. left-right)
symmetry of the entire system. These broken-symmetry states are the
high-transmission nonlinear modes of the system. We also discuss how to excite
these states.Comment: 5 pages, 5 figure
Dual-purpose wheat: Management for forage and grain production
The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
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