Multistep Parametric Processes in Nonlinear Optics

We present a comprehensive overview of different types of parametric interactions in nonlinear optics which are associated with simultaneous phase-matching of several optical processes in quadratic nonlinear media, the so-called multistep parametric interactions. We discuss a number of possibilities of double and multiple phase-matching in engineered structures with the sign-varying second-order nonlinear susceptibility, including (i) uniform and non-uniform quasi-phase-matched (QPM) periodic optical superlattices, (ii) phase-reversed and periodically chirped QPM structures, and (iii) uniform QPM structures in non-collinear geometry, including recently fabricated two-dimensional nonlinear quadratic photonic crystals. We also summarize the most important experimental results on the multi-frequency generation due to multistep parametric processes, and overview the physics and basic properties of multi-color optical parametric solitons generated by these parametric interactions.Comment: To be published in Progress in Optic

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

HOW FINTECH IS DOING INNOVATIONS AND EFFICIENCY IN THE BANKING SECTOR?

Purpose - the purpose of the research is to examine the impact of fintech on bank efficiency in the Asian banking industry, where bank efficiency has been measured using the DEA (data envelopment analysis) approach for technical efficiency as a proxy. Methodology - the methodology of the research includes the sample consisting of 92 privatized commercial Asian banks from 2016-2022 and uses cross-country analysis. The panel regression models have been utilized, consisting of a fixed effect model. The model has run after the diagnostic check and the data validation has been satisfied with the stationary, serial autocorrelation, heteroscedasticity, homogeneity and multicollinearity issues. Results - The results show that fintech funding has a significantly positive effect on bank efficiency. Based on the results, it concludes that fintech funding is doing innovations using funding and improving efficiency in Asian banks. Implication - the implication derived from the empirical evidence of the study is that fintech funding brings innovations that positively consequence on bank efficiency in Asian banks. Limitation - the limitation of the study is that there was no data available before 2016 since fintech was a new technology during the time