Polarization resolved Cu L3L_3-edge resonant inelastic x-ray scattering of orbital and spin excitations in NdBa2_{2}Cu3_{3}O7−δ_{7-\delta}

High resolution resonant inelastic x-ray scattering (RIXS) has proven particularly effective in the determination of crystal field and spin excitations in cuprates. Its strength lies in the large Cu $L_{3}$ resonance and in the fact that the scattering cross section follows quite closely the single-ion model predictions, both in the insulating parent compounds and in the superconducting doped materials. However, the spectra become increasingly broader with (hole) doping, hence resolving and assigning spectral features has proven challenging even with the highest energy resolution experimentally achievable. Here we have overcome this limitation by measuring the complete polarization dependence of the RIXS spectra as function of momentum transfer and doping in thin films of NdBa$_{2}$Cu$_{3}$O$_{7-\delta}$. Besides confirming the previous assignment of $dd$ and spin excitations (magnon, bimagnon) in the antiferromagnetic insulating parent compound, we unequivocally single out the actual spin-flip contribution at all dopings. We also demonstrate that the softening of $dd$ excitations is mainly attributed to the shift of the $xy$ peak to lower energy loss. These results provide a definitive assessment of the RIXS spectra of cuprates and demonstrate that RIXS measurements with full polarization control are practically feasible and highly informative.Comment: 14 pages, 10 figure

Three-dimensional CFD simulations with large displacement of the geometries using a connectivity-change moving mesh approach

This paper deals with three-dimensional (3D) numerical simulations involving 3D moving geometries with large displacements on unstructured meshes. Such simulations are of great value to industry, but remain very time-consuming. A robust moving mesh algorithm coupling an elasticity-like mesh deformation solution and mesh optimizations was proposed in previous works, which removes the need for global remeshing when performing large displacements. The optimizations, and in particular generalized edge/face swapping, preserve the initial quality of the mesh throughout the simulation. We propose to integrate an Arbitrary Lagrangian Eulerian compressible flow solver into this process to demonstrate its capabilities in a full CFD computation context. This solver relies on a local enforcement of the discrete geometric conservation law to preserve the order of accuracy of the time integration. The displacement of the geometries is either imposed, or driven by fluid–structure interaction (FSI). In the latter case, the six degrees of freedom approach for rigid bodies is considered. Finally, several 3D imposed-motion and FSI examples are given to validate the proposed approach, both in academic and industrial configurations

Theory in highly cited studies of sexual minority parent families: variations and implications

This paper includes a systematic review and citation analysis of the literature regarding sexual minority parent families, particularly attending to what theories have been used, and how. We consider the importance of theoretical frameworks for future research and implications for policy, practice, and law related to sexual minority parent families. Our review targets 30 highly cited studies located through Google Scholar (as an interdisciplinary search engine) and published within a specific time frame (2005-2010). We highlight the dominant theoretical models employed across disciplines studying sexual minority parent families. While the majority of studies reviewed referred to theoretical models or perspectives, explicit theoretical grounding was frequently lacking. Instead, the empirical work reviewed appeared to have a predominantly applied focus in addressing public debates on sexual minority parent families. We provide recommendations for how theory might be more fully integrated into the social science literature on sexual minority parents and their children