Optimized generation of spatial qudits by using a pure phase spatial light modulator

We present a method for preparing arbitrary pure states of spatial qudits, namely, D-dimensional (D > 2) quantum systems carrying information in the transverse momentum and position of single photons. For this purpose, a set of D slits with complex transmission are displayed on a spatial light modulator (SLM). In a recent work we have shown a method that requires a single phase-only SLM to control independently the complex coefficients which define the quantum state of dimension D. The amplitude information was codified by introducing phase gratings inside each slit and the phase value of the complex transmission was added to the phase gratings. After a spatial filtering process we obtained in the image plane the desired qudit state. Although this method has proven to be a good alternative to compact the previously reported architectures, it presents some features that could be improved. In this paper we present an alternative scheme to codify the required phase values that minimizes the effects of temporal phase fluctuations associated to the SLM where the codification is carried on. In this scheme the amplitudes are set by appropriate phase gratings addressed at the SLM while the relative phases are obtained by a lateral displacement of these phase gratings. We show that this method improves the quality of the prepared state and provides very high fidelities of preparation for any state. An additional advantage of this scheme is that a complete 2\pi modulation is obtained by shifting the grating by one period, and hence the encoding is not limited by the phase modulation range achieved by the SLM. Numerical simulations, that take into account the phase fluctuations, show high fidelities for thousands of qubit states covering the whole Bloch sphere surface. Similar analysis are performed for qudits with D = 3 and D = 7.Comment: 12 pages, 7 figure

High-velocity impact on composite sandwich structures: A theoretical model

A theoretical energy-based model to capture the ballistic response of sandwich structures made of composite material peels and a crushable foam core was developed. The model was based on the wave propagation theory and it was split in six stages with their corresponding energy-absorption mechanisms. The division of the stages was based on the physical interpretation of the perforation process involving reasonable hypotheses and simplifications. The energy-absorption was analysed at velocities below, near and above the ballistic limit within all the stages showing the general trends in terms of their relative importance. The time and velocity at each stage was separately analysed within a wide range of velocities in order to see the stage contribution to the energy-absorption. The model was validated against experimental results obtained in the literature showing a good agreement in terms of the impact-residual velocity curve. © 2021 The Author(s

Стратегия развития электронного правительства Мексики федеральной администрацией в 2012-2018 гг.

Technological developments have already had an impact in the way people shop, work an

Phosphorus release kinetics in a soil amended with biosolids and vermicompost

Wastewater biosolids are large potential sources of macronutrients for agriculture, conservation and restoration of soils; there are, however, few studies on phosphorus (P) release in soils amended with biosolids. Biosolids and vermicomposted biosolids were tested in concentrations (5–30 g amendment kg-1 soil) equivalent to 18–100 Mg ha-1. Desorption of P was determined by successive extractions for 65 days. Soil P was low, and biosolid and vermicompost addition released 8 and 6 times more P, respectively, than soil alone. To describe the release of P, zero-, first- and second-order equations, simple Elovich and power functions and the parabolic diffusion lawwere compared based on their coefficient of determination (r2) and standard error (SE). In all treatments, the power function and especially the parabolic diffusion law were the best fit, with 0.898–0.996 r2 and 0.022–0.732 SE. The general behavior of the kinetic parameters mostly depended on the amendment doses. Eutrophication posited to start beyond 16 mg P kg-1 soil was more likely allayed by a maximum vermicompost dose of 50 Mg ha-1, higher than the 36 Mg ha-1 maximum biosolid dose. The higher vermicompost P addition and lower P release could favor gradual and longer-term P absorption by plants and may reduce leaching or runoff P losses