937 research outputs found
Deterministic Transformations of Multipartite Entangled States with Tensor Rank 2
Transformations involving only local operations assisted with classical
communication are investigated for multipartite entangled pure states having
tensor rank 2. All necessary and sufficient conditions for the possibility of
deterministically converting truly multipartite, rank-2 states into each other
are given. Furthermore, a chain of local operations that successfully achieves
the transformation has been identified for all allowed transformations. The
identified chains have two nice features: (1) each party needs to carry out at
most one local operation and (2) all of these local operations are also
deterministic transformations by themselves. Finally, it is found that there
are disjoint classes of states, all of which can be identified by a single real
parameter, which remain invariant under deterministic transformations.Comment: 27 pages, 1 figure; added new references and improved the
presentatio
Carrier-induced refractive index change and optical absorption in wurtzite InN and GaN: Fullband approach
Based on the full band electronic structure calculations, first we consider
the effect of n-type doping on the optical absorption and the refractive index
in wurtzite InN and GaN. We identify quite different dielectric response in
either case; while InN shows a significant shift in the absorption edge due to
n-type doping, this is masked for GaN due to efficient cancellation of the
Burstein-Moss effect by the band gap renormalization. For high doping levels
the intraband absorption becomes significant in InN. Furthermore, we observe
that the free-carrier plasma contribution to refractive index change becomes
more important than both band filling and the band gap renormalization for
electron densities above 10~cm in GaN, and 10~cm in
InN. As a result of the two different characteristics mentioned above, the
overall change in the refractive index due to n-type doping is much higher in
InN compared to GaN, which in the former exceeds 4\% for a doping of
10~cm at 1.55~m wavelength. Finally, we consider intrinsic
InN under strong photoexcitation which introduces equal density of electron and
holes thermalized to their respective band edges. The change in the refractive
index at 1.55~m is observed to be similar to the n-doped case up to a
carrier density of 10~cm. However, in the photoexcited case this
is now accompanied by a strong absorption in this wavelength region due to
intravalence band transition. Our findings suggest
that the alloy composition of InGaN can be optimized in the
indium-rich region so as to benefit from high carrier-induced refractive index
change while operating in the transparency region to minimize the losses. These
can have direct implications for InN-containing optical phase modulators and
lasers.Comment: Revised with an appendix, two additional figures, and more
discussions; 10 pages, 14 figures; published versio
The optimization of voltage parameter for tissue electroporation in somatic embryos of Astragalus chrysochlorus (Leguminosae)
Somatic embryo tissues of Astragalus chrysochlorus were transformed with the b-glucuronidase (GUS) and neomycin phosphotransferase II (npt II) genes by electroporation. The effect of electric field strength was tested for transient expression. It was found that 1000 V/cm and 200 ms and 1 pulse wasthe optimum combination to transform embryo tissues (expression level was 61.5%). Electroporated somatic embryo tissues were positive for GUS expression and PCR analysis for the genes GUS and npt II. After PCR analysis, we found that the efficiency of the somatic embryos with transient GUS expression by electroporation was 48%
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Wind control on the accumulation of heavy metals in sediment of Lake Ulubat, Anatolia, Turkey
Freshwater Lake Ulubat (zmean = 1.5-2.0 m and Area = ~138 km2), NW Anatolia, Turkey was filled in by fine-to-medium-grain silts during the late Holocene. Deposition in Lake Ulubat has been 1.6 cm yr-1 for the last 50 years, but the sedimentation rate over the last ~1,600 years was lower (0.37 mm yr-1). The organic matter and carbonate contents of the infill show cyclic changes that reflect environmental fluctuations. The silt-dominated lithology and the vertically uniform heavy metal distributions are probably due to wind-controlled sedimentation in the lake. Heterogeneous mud, derived from a large, mountainous drainage basin, is deposited in the lake mostly during summer, June to October, when conditions are hot and calm. Winter months are stormier and sediments are re-suspended due to the shallow water depth and the effect of waves on the lake bottom. It is likely that re-suspended sediments, particularly fine-grained particles, together with the heavy metals, are transported out of the lake via the outlet, especially during periods of high lake level. This resuspension and removal process probably caused the lake sediments to become silt-dominated and depleted in heavy metals. The role of broad shallow lakes in sequestering sediments and heavy metals can be described more accurately when wind data are considered. Such information may also be helpful for land-use planning in downstream areas
Gauge covariance and spin-current conservation in the gauge-field formulation of systems with spin–orbit coupling
The question of gauge covariance in the non-Abelian gauge-field formulation of two space-dimensional systems with spin-orbit coupling relevant to spintronics is investigated. Although these are generally gauge-fixed models, it is found that for the class of gauge fields that are spacetime independent and satisfy a U(1) algebra, thus having a vanishing field strength, there is a residual gauge freedom in the Hamiltonian. The gauge transformations assume the form of a space-dependent rotation of the transformed wavefunctions with rotation angles and axes determined by the specific form of the gauge field, i.e. the spin-orbit coupling. The fields can be gauged away, reducing the Hamiltonian to one which is isospectral to the free-particle Hamiltonian, and giving rise to the phenomenon of persistent spin helix reported first by Bernevig et al (2006 Phys. Rev. Lett. 97 236601). The investigation of the global gauge transformations leads to the derivation of a continuity equation where the component of the spin density along given directions, again fixed by the specific form of the gauge field, is conserved
Drying kinetic and physical properties of green laird lentil (Lens culinaris) in microwave drying
The objective of this study was to study the drying kinetics of green laird lentil (Lens culinaris) in microwave drying method. The drying data were fitted to the various thin-layer models. All the models were compared using three statistical parameters, that is, coefficient of determination R2, reduced mean square of the deviation X2 and root means square error RMSE. Also, the lentil’s physical and mechanical features crude protein, oil and ash parameters were specified under different microwave levels. It was concluded according to these values that the recommended model is the best model, which can define the drying curves at the practices at 300, 400, 550, 700 and 800 W in drying lentil by microwave.Key words: Microwave, lentil, physical properties, crude protein, drying
Hadron Production in Neutrino-Nucleon Interactions at High Energies
The multi-particle production at high energy neutrino- nucleon collisions are
investigated through the analysis of the data of the experiment CERN-WA-025 at
neutrino energy less than 260GeV and the experiments FNAL-616 and FNAL-701 at
energy range 120-250 GeV. The general features of these experiments are used as
base to build a hypothetical model that views the reaction by a Feynman diagram
of two vertices. The first of which concerns the weak interaction between the
neutrino and the quark constituents of the nucleon. At the second vertex, a
strong color field is assumed to play the role of particle production, which
depend on the momentum transferred from the first vertex. The wave function of
the nucleon quarks are determined using the variation method and relevant
boundary conditions are applied to calculate the deep inelastic cross sections
of the virtual diagram.Comment: 6 pages PDF forma
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