Energy spectra of two interacting fermions with spin-orbit coupling in a harmonic trap

We explore the two-body spectra of spin-$1/2$ fermions in isotropic harmonic traps with external spin-orbit potentials and short range two-body interactions. Using a truncated basis of total angular momentum eigenstates, non-perturbative results are presented for experimentally realistic forms of the spin-orbit coupling: a pure Rashba coupling, Rashba and Dresselhaus couplings in equal parts, and a Weyl-type coupling. The technique is easily adapted to bosonic systems and other forms of spin-orbit coupling.Comment: 12 pages, 9 figure

Common-mode rejection in Martin-Puplett spectrometers for astronomical observations at mm-wavelengths

The Martin-Puplett interferometer (MPI) is a differential Fourier transform spectrometer (FTS), measuring the difference between spectral brightness at two input ports. This unique feature makes the MPI an optimal zero instrument, able to detect small brightness gradients embeddend in a large common background. In this paper we investigate experimentally the common-mode rejection achievable in the MPI at mm wavelengths, and discuss the use of the instrument to measure the spectrum of cosmic microwave background (CMB) anisotropy

Enjoy liberty as we learn its meaning. Obergefell v. Hodges tra libertà, uguaglianza e pari dignità

On June 26, 2015, US Supreme Court ruled on the issue of same-sex marriage, finally recognizing the right to marry for same-sex couples, as well as the duty of each State to recognize same-sex mar-riages celebrated in another State. The article analyzes the decision as a milestone in the history of the struggle for civil rights of gay and lesbians in the US and abroad. From a constitutional perspec-tive, the article highlights the original combination of due process and equal protection clause in the interpretation of the Fourteenth Amendment. It shows a new form of interaction between the concepts of liberty and equality, and a significant use of the concept of dignity. Keywords: same-sex marriage; liberty; dignity; equality; civil rights; Supreme Court of the United States of America

Pensione di reversibilità e coppie omosessuali. quadro comparativo

SOMMARIO: 1. Premessa. Il ddl sulle unioni civili e i diritti previdenziali - 2. Matrimonio same sex, unioni civili e coppie di fatto alla prova della parità di trattamento - 2.1 Lo “stato dell’arte” nell’UE - 2.2 La situazione italiana - 2.3 La parità di trattamento delle coppie omosessuali nella giurisprudenza delle Corti europee - 3. Quadro comparativo - 3.1 Spagna - 3.2 Portogallo - 3.3 Francia - 3.4. Regno Unito e Irlanda - 3.5. Germania e Austria - 4. Conclusion

Governo dell’economia e gestione dei conflitti nell’Unione europea. appunti sul principio di solidarietà

L’articolo analizza le diverse dimensioni del principio di solidarietà nel contesto del costituzionalismo europeo contemporaneo, avuto riguardo sia al diritto dell’Unione europea, sia all’incidenza del processo di integrazione sulle dinamiche costituzionali interne. In particolare, l’analisi del principio è inquadrata con riguardo alla gestione dei conflitti sorti in conseguenza della crisi economica e finanziaria che ha interessato l’Europa negli ultimi anni. Nella prima parte dell’articolo, si analizza il rilievo del principio di solidarietà nell’applicazione degli strumenti interni di controllo sulle misure di austerità adottate in conseguenza della crisi, anche in relazione al rapporto tra principio di solidarietà e pluralismo territoriale. Nella seconda parte dell’articolo, specificamente dedicata all’ordinamento dell’Unione europea vengono prese in esame quattro dimensioni del principio nel diritto dell’Unione (solidarietà fra stati, solidarietà fra cittadini, apertura del principio alla dimensione politica e compresenza di obblighi di prestazione, obblighi di lealtà e obblighi di responsabilità) analizzando la giurisprudenza della Corte di giustizia che ha fatto applicazione del principio e, soprattutto, l’ambiguo carattere solidaristico delle misure di sostegno agli stati membri in difficoltà. In conclusione, l’Autore riflette, a partire dalle esperienze analizzate nel corso dell’articolo, sul legame tra solidarietà e conflitti, mettendo in luce come la dimensione normativa del principio – pur con le ambiguità che le sono connaturate – possa rappresentare uno strumento di gestione dei conflitti, senza negarne la valenza costitutiva nella dimensione politica

Le unioni civili tra persone dello stesso sesso. profili di diritto comparato e tenuta del principio di uguaglianza

SOMMARIO: 1. Il riconoscimento della vita familiare omosessuale nel diritto comparato ed europeo: esperienza tedesca ed esperienza italiana a confronto. – 2. Unione civile e matrimonio: garanzia di istituto e tenuta del principio di uguaglianza. – 3. Le peculiarità dell’esperienza italiana: il comma 20 della legge n. 76/2016. – 4. Segue: la portata del comma 20 alla luce dell’attuazione della legge. - 5. Rilivi conclusiv

DNS of multiphase flows: study of atomization and free-surface phenomena

The present thesis focuses on the numerical analysis of some diverse physical set-up that involve the interaction of two -or three immiscible and incompressible phases. The simulations are carried out by means of finite-volume algorithms developed on the in-house Computational Fluid Dynamics platform TermoFluids, developed by the Heat and Mass Transfer Technological Center (CTTC). They are intended to give detailed insights on the physics of the analyzed phenomena by carrying out Direct Numerical Simulations (DNS). In the context of multiphase flows, namely, Computational Multi-Fluid Dynamics (CMFD) field, DNS means that all the interfacial and turbulent scales of the phenomenon must be fully resolved. In the Introduction, a general overview of the engineering applications and the computational methods related to multiphase flows is proposed. The various types of physics analyzed in this work and the numerical approaches applied here to carry out efficient simulations are introduced. In Chapter 2, a low-dissipation convection scheme for the stable discretization of multiphase flow by means of interface-capturing schemes is analyzed. The hybrid form of the convective operator proposed incorporates localized low-dispersion characteristics to limit the growth of spurious flow solutions. Moreover, in comparison to pure-dissipative schemes, the discretization aims at minimizing the differences in kinetic energy preservation with respect to the continuous governing equations. This property plays a fundamental role in the case of flows presenting significant levels of turbulence. The simulation of a turbulent 2D coaxial jet with the low-dissipation convection scheme demonstrates its capability of solving correctly the two-phase turbulent problems. In Chapter 3, all the work carried out on the simulation of two-phase flow with the aid of Adaptive Mesh Refinement (AMR) strategies is described. The model is globally addressed at improving the representation of interfacial and turbulent scales in general multiphase flows. It is first applied to the simulation of simple multiphase phenomena, as 2D and 3D rising bubbles, to demonstrate the convergence of the method and the important computational savings in comparison to static mesh computations. However, its adoption becames essential in the simulation of instability and break-up phenomena, where the necessity of representing accurately the complex structures that appear at the interface, as ligaments and droplets, make the simulation particularly expensive in terms of computational cost. In Chapter 4, we analyze in detail the simulations of 3-D atomizing phenomena, including the coaxial jet case, characterized by the parallel injection of high speed liquid and gas fluxes, and the liquid spray case, characterized by the injection of a high speed liquid inside a still air chamber. In Chapter 5, an original single-phase scheme for the DNS of free-surface problems on 3-D unstructured meshes is presented. The scheme is based on a novel treatment of the interface for the deactivation of the light-phase, allowing an optimization of the classic two-phase model for the cases in which the influence of the lighter phase is negligible. Consequently, the model is particularly addressed at analyzing problems involving the movement of free-surfaces, as the evolution of waves on the sea, and their interaction with fixed and moving obstacles. Some practical cases of application are proposed, as the evaluation of stresses on an object due to the action of a dam-break event, and the interaction of linear waves with an oscillating water column device. In the same Chapter we describe the procedure to couple the single-phase model to the Immersed Boundary Method. The method is aimed at representing the interaction of a solid moving with prescribed velocity and the two-phase flow. The most significant example consists in the simulation of a sliding wedge into a liquid basin.Esta tesis se focaliza en la simulación numérica de algunos set-up físicos que involucran la interacción entre dos o tres fluidos incompresibles y immiscibles. Las simulaciones se realizan por medio de algoritmos de volúmenes-finitos desarrollados en la plataforma propia de Fluido-Dinámica Computacional (CFD) denominada TermoFluids, desarrollada en el Centro Tecnologico de Trasferencia de Calor (CTTC). Las simulaciones quieren estudiar en detalle la física de los fenómenos analizados, realizando su Simulación Numérica Directa (DNS). En el contexto de los flujos multifase, DNS significa que todas las escalas interfaciales y turbulentas del fenómeno han de ser totalmente resueltas. En la Introducción, se propone una panorámica general de las aplicaciones de ingeniería y de los métodos computacionales relacionados con flujos multifases. Se introducen los varios tipos de física analizados en este trabajo y las estrategias numéricas aplicadas aquí para efectuar su simulación de manera eficiente. En el Capitulo 2 se analiza un esquema convectivo de baja-disipación para la discretization de flujo multifase por medio de métodos de interface-capturing. La forma híbrida del operador convectivo propuesto incorpora la característica de una baja dispersión localizada, focalizada en limitar el crecimiento de soluciones numéricas espurias. Además, en comparación con métodos disipativos puros, la discretización apunta a minimizar las diferencias en la conservación de energía cinética en respeto a las ecuaciones continuas que gobiernan el flujo. Esta propiedad juega un papel fundamental en el caso de flujo caracterizado por un alto nivel de turbulencia. La simulación de un jet 2D coaxial turbulento con el método convectivo de baja disipación demuestra su capacidad de resolver correctamente un flujo de dos fases turbulentos. En el Capitulo 3 se reporta todo el trabajo realizado sobre la simulación de flujo multifase con el auxilio de técnicas de refinamiento adaptativo de malla (AMR). El modelo es globalmente dirigido a la mejora de la representación de las escalas turbulentas y interfaciales en flujos multifases en general. Se aplica inicialmente a la simulación de flujos sencillos, como unos casos de burbujas flotantes 2D y 3D, demostrando la convergencia del método y los importantes ahorros computacional en comparación con los cálculos de mallas estáticas. La adopción de la técnica se hace esencial en la simulación de fenómenos de inestabilidad y de ruptura, donde la necesidad de representar sacramentalmente las estructuras complejas que aparecen en la interfaz, como ligamentos o pequeñas gotas, hacen que la simulación sea particularmente pesada en términos de coste computacional. En el Capitulo 4 se reportan en detalle las simulaciones de fenómenos de atomización 3D. Esas incluyen el caso del jet coaxial, caracterizado por la inyección paralela de flujos de aire y liquido de altas velocidades, y el caso del spray liquido, que consiste en la inyección de un liquido dentro de una cámara de aire. En el Capitulo 5 se presenta un esquema de single-phase original, para el DNS de problemas de superficie libre en mallas 3D no-estructuradas. El esquema se basa en un nuevo tratamiento de la interfase para la desactivación de la fase ligera, permitiendo la optimización del solver clásico de dos fases para los casos en que la influencia de la fase mas ligera sea despreciable. En consecuencia, el modelo es particularmente indicado para la análisis de problemas que involucran el movimiento de superficies libres, como la evolución de olas en la superficie marina y su interacción con obstáculos fijos o muebles. Se proponen algunos casos prácticos de aplicación, como la evaluación de las fuerzas sobre un objeto debidos a un episodio de dam-break, o el estudio de las olas generadas por el impacto de un solido deslizante (representado integrando la tecnica de Immersed Boundary con el presente metodo de single-phase) con un embalse de agua