Coarse-grained tight-binding models

Calculating the electronic structure of systems involving very different length scales presents a challenge. Empirical atomistic descriptions such as pseudopotentials or tight-binding models allow one to calculate the effects of atomic placements, but the computational burden increases rapidly with the size of the system, limiting the ability to treat weakly bound extended electronic states. Here we propose a new method to connect atomistic and quasi-continuous models, thus speeding up tight-binding calculations for large systems. We divide a structure into blocks consisting of several unit cells which we diagonalize individually. We then construct a tight-binding Hamiltonian for the full structure using a truncated basis for the blocks, ignoring states having large energy eigenvalues and retaining states with an energy close to the band edge energies. A numerical test using a GaAs/AlAs quantum well shows the computation time can be decreased to less than 5% of the full calculation with errors of less than 1%. We give data for the trade-offs between computing time and loss of accuracy. We also tested calculations of the density of states for a GaAs/AlAs quantum well and find a ten times speedup without much loss in accuracy.

Fragmentation of charmed quark to double-charmed hadrons

We consider the production of hadrons containing two charmed quarks in pp and ee collisions. We perform a numerical comparison of the fragmentation approach with the full calculation at $${{{\mathcal {O}}}}(\alpha _s^4)$$ O ( α s 4 ) . We conclude that the non-fragmentation contributions remain important up to transverse momenta as large as about 40 GeV, thus making questionable the applicability of the fragmentation approximation at smaller transverse momenta.

LEGAL ASPECT OF PAYMENT OF THE AVERAGE AMOUNT OF CASH SUPPLY TO MILITARY SERVANTS ON THE BASIS OF A COURT DECISION

The article analyzes the problematic issues regarding the payment of cash benefits to servicemen in case of violation of the term of obligatory social benefits upon dismissal. It is determined that during 2018–2020 there is a practice of applying the norms of labor legislation of Ukraine to recover from the military units of the Armed Forces of Ukraine the average amount of cash during the delay of full payment of a serviceman upon discharge from military service. It is noted that this state of affairs puts excessive financial pressure on the state defense budget, and therefore it is necessary to clarify the legitimacy of the application of labor legislation to servicemen in terms of payment of the average amount of cash for the delay in discharge from military service. It is substantiated that the norms of special legislation have an exclusive advantage over the norms of labor legislation in resolving disputes concerning the full calculation of servicemen upon discharge from military service. Emphasis is placed on the fact that the practice of the European Court of Human Rights regarding the payment of average earnings to individual citizens of Ukraine during the delay in payment upon dismissal is ambiguous. It was found that at the regulatory level there is no procedure for calculating the average amount of cash collateral. It is noted that the application of the analogy of the procedure for calculating the average salary of employees is technically impossible given that the structure of monetary support of servicemen and its economic essence is different from the structure and nature of wages. It is proposed as a direction of further research to develop a compromise mechanism in the system of special legislation to strengthen the responsibility of officials of military units of the Armed Forces of Ukraine for late and incomplete payment of servicemen upon discharge from military service.

NLO QCD corrections to off-shell $$ \mathrm{t}\overline{\mathrm{t}}{\mathrm{W}}^{\pm } $$ production at the LHC

We present results of a computation of NLO QCD corrections to the production of an off-shell top-antitop pair in association with an off-shell W+ boson in proton-proton collisions. As the calculation is based on the full matrix elements for the process $$ \mathrm{pp}\to {\mathrm{e}}^{+}{v}_{\mathrm{e}}{\mu}^{-}{\overline{v}}_{\mu }{\tau}^{+}{v}_{\tau}\mathrm{b}\overline{\mathrm{b}} $$ pp → e + v e μ − v ¯ μ τ + v τ b b ¯ , all off-shell, spin-correlation, and interference effects are included. The NLO QCD corrections are about 20% for the integrated cross-section. Using a dynamical scale, the corrections to most distributions are at the same level, while some distributions show much larger K-factors in suppressed regions of phase space. We have performed a second calculation based on a double-pole approximation. While the corresponding results agree with the full calculation within few per cent for integrated cross-sections, the discrepancy can reach 10% and more in regions of phase space that are not dominated by top-antitop production. As a consequence, on-shell calculations should only be trusted to this level of accuracy.

Fast Prediction of Contrast Detection Probability

Contrast detection probability (CDP) is proposed as an IEEE P2020 metric to predict camera performance intended for computer vision tasks for autonomous vehicles. Its calculation involves comparing combinations of pixel values between imaged patches. Computation of CDP for all meaningful combinations of m patches involves approximately 3/2(m2-m).n4 operations, where n is the length of one side of the patch in pixels. This work presents a method to estimate Weber contrast based CDP based on individual patch statistics and thus reduces to computation to approximately 4n2m calculations. For 180 patches of 10×10 pixels this is a reduction of approximately 6500 times and for 180 25×25 pixel patches, approximately 41000. The absolute error in the estimated CDP is less than 0.04 or 5% where the noise is well described by Gaussian statistics. Results are compared for simulated patches between the full calculation and the fast estimate. Basing the estimate of CDP on individual patch statistics, rather than by a pixel-to-pixel comparison facilitates the prediction of CDP values from a physical model of exposure and camera conditions. This allows Weber CDP behavior to be investigated for a wide variety of conditions and leads to the discovery that, for the case where contrast is increased by decreasing the tone value of one patch and therefore increasing noise as contrast increases, there exists a maxima which yields identical Weber CDP values for patches of different nominal contrast. This means Weber CDP is predicting the same detection performance for patches of different contrast.

A full treatment of peculiar velocities on the reionization light cone

ABSTRACT Accurate simulations of the 21-cm signal from the Epoch of Reionization require the generation of maps at specific frequencies given the values of astrophysical and cosmological parameters. The peculiar velocities of the hydrogen atoms producing the 21-cm radiation result in a shift in the observed frequency of the 21-cm radiation and changes the amplitude of the signal itself. This is not an effect we can remove but instead needs to be accurately modelled to ensure we infer the correct physical parameters from an observation. We describe the full calculation of the distortion of the 21-cm signal, and propose a new code that integrates the 21-cm intensity along the line of sight for each individual light cone pixel to fully capture the intensity contributions from multiple redshifts. This algorithm naturally deals with the typical divergences found in standard approaches, allowing for large optical depths and 21-cm absorption events at high redshifts. We find the new method results in up to a 60 per cent decrease in power on the largest scales on the sky, and an increase of over 80 per cent on the smallest scales on the sky. We find that the new implementation of the light cone results in a longer tail of bright temperatures in the brightness temperature distribution, as a result of the successful circumventing of a previous cap that had to be implemented to avoid a divergence in the brightness temperature. We conclude that this full treatment of the evolution of the light cone pixel can be an important effect.

THE IMPACT OF ENTREPRENEURIAL BEHAVIOR ON SALES VOLUME

This research was conducted at the Culinary Hawkers that located on Highway Sukapura, Dayeuhkolot, Bandung. This study examines the Entrepreneurial behaviour which resulted in increased sales volumes. Almost all Culinary Hawkers on Highway Sukapura doesn’t yet have the entrepreneurial behavior in accordance with the characteristics - traits mentioned by Suryana, Confident, Own initiative, Have achievement motive, Having leadership, and Dare to take risks with the full calculation. The purpose of this study was to investigate the influence of entrepreneurial behavior to the merchant's sales volume culinary pavement on Highway Sukapura, Dayeuhkolot, Bandung.Researchers used quantitative research methods. The population in this study was 63 Merchants Culinary Street on Highway Sukapura. Samples are 63 street vendors in JalanSukapura. Data were analyzed using simple regression analysis.The results showed that entrepreneurial behavior affect the sales volume of culinary street traders in Highway Sukapura. Based on the calculation coefficient of determination (R2) can be seen the effect of entrepreneurial behavior variables (X) on sales volume (Y) is approximately 94%. While the remaining 6% are influenced by other factors such as competence, performance, and motivation.