Search results for "SCA"
showing 10 items of 23299 documents
Proximity Effect in Superconducting Heterostructures with Strong Spin-Orbit Coupling and Spin Splitting
2019
It has been shown that singlet Cooper pairs can be converted into triplet ones and diffuse into a ferromagnet over a long distance in a phenomenon known as the long-range proximity effect (LRPE). This happens in materials with inhomogeneous magnetism or spin-orbit coupling (SOC). Most of the previous studies focus on the cases with small SOC and exchange field. However, the physics was not clear when SOC and exchange field strength are both much greater than the disorder strength. In this work, we consider a two dimensional system with a large Rashba-type SOC and exchange field in the case where only one band is partially occupied. We develop a generalized quasiclassical theory by projectin…
Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
2019
We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for microscopic tight-binding and low-energy continuum models. We predict qualitative differences between local and non-local interaction schemes which could be distinguished experimentally. In the flat band limit where the pair potential exceeds the band width we show that the superfluid weight and BKT temperature are determined by multiband processes and quantum geometry of the band.
Field dependence of the vortex-core sizes in dirty two-band superconductors
2019
We study the structure of Abrikosov vortices in two-band superconductors for different external magnetic fields and different parameters of the bands. The vortex core size determined by the coherence lengths are found to have qualitatively different behaviour from that determined by the quasiparticle density of states spatial variation. These different vortex core length scales coincide near the upper critical field, while the discrepancy between them becomes quite significant at lower fields. Within the diffusive approximation we demonstrate several generic regimes in the field dependence of the vortex core sizes determined by the disparity of diffusion constants in the two bands.
Time-dependent quantum transport in nanosystems : a nonequilibrium Green's function approach
2016
A time-dependent extension to the Landauer–Büttiker approach to study transient quantum transport in arbitrary junctions composed of leads and conducting devices is developed. The nonequilibrium Green’s function approach is employed for describing the charge and heat transport dynamics. The importance of the developed method is that it provides a closed formula for the time-dependent density matrix in both electronic and phononic systems. In the electronic case the nonequilibrium conditions are due to a switch-on of a bias voltage in the leads or a perturbation in the junction whereas in the phononic case the central region of interest is coupled to reservoirs of di erent temperatures. In b…
Scattering of Co-Current Surface Waves on an Analogue Black Hole
2018
We report on what is to our knowledge the first scattering experiment of surface waves on an accelerating transcritical flow, which in the analogue gravity context is described by an effective spacetime with a black-hole horizon. This spacetime has been probed by an incident co-current wave, which partially scatters into an outgoing countercurrent wave on each side of the horizon. The measured scattering amplitudes are compatible with the predictions of the hydrodynamical theory, where the kinematical description in terms of the effective metric is exact.
IMPIEGO DI SCAFFOLD SINTETICO PER IL TRATTAMENTO E LA PREVENZIONE DEL LAPAROCELE – MODELLO SPERIMENTALE NELLA CHIRURGIA RIGENERATIVA
2022
Automatic surrogate modelling technique selection based on features of optimization problems
2019
A typical scenario when solving industrial single or multiobjective optimization problems is that no explicit formulation of the problem is available. Instead, a dataset containing vectors of decision variables together with their objective function value(s) is given and a surrogate model (or metamodel) is build from the data and used for optimization and decision-making. This data-driven optimization process strongly depends on the ability of the surrogate model to predict the objective value of decision variables not present in the original dataset. Therefore, the choice of surrogate modelling technique is crucial. While many surrogate modelling techniques have been discussed in the liter…
SUSSIDIARIETA’ E FISCALITA’: UN NUOVO MODO DI CONCEPIRE IL CONCORSO ALLE SPESE PUBBLICHE?
2017
I rapporti fra il pubblico ed il privato si stanno progressivamente modificando. La coscienza del partecipare alla cosa pubblica si evolve ed assume nuove forme di manifestazione. Fra esse un ruolo centrale gioca la partecipazione dei cittadini cd “attivi” che, sia singolarmente che in forma associata, assumono volontariamente la cura di beni che hanno rilevanza collettiva, e quindi beni “comuni”, che spetterebbe al potere pubblico tutelare. E’ il tema della cd. “sussidiarietà orizzontale”. Scopo del presente scritto è quello di analizzarne i possibili rapporti con la fiscalità e, segnatamente, rispondere alla domanda se, ed in che misura, i tributi possano essere uno strumento incentivante…
’Green’ strategies and approaches. A contribution from the off-site and upcycling of discarded shipping containers
2021
La Terra versa oggi in una condizione di vulnerabilità che gran parte degli studiosi attribuisce a un modello di crescita infinita inseguita su un pianeta con risorse limitate. In relazione a questo contesto ambientale critico il contributo si propone di stimolare nuove prassi per il settore delle costruzioni suggerendo una visione sistemica che faccia ricorso contemporaneamente a più approcci sostenibili e circolari e che, combinando tecniche e tecnologie tradizionali e innovative, consenta l’eliminazione di scarti e rifiuti. In particolare, l’articolo illustra le potenzialità della prefabbricazione nel contenimento degli impatti ambientali diretti e indiretti rispetto a un’equivalente cos…
DEVELOPMENT OF SUSTAINABLE METROPOLITAN AREAS USING A MULTI-SCALE DECISION SUPPORT SYSTEM
2012
A sustainable and sustaining planning strategy is globally important for metropolitan areas. Sustainable planning addresses the development of strategies to reduce the use of resources, increase economic efficiency and improve integration of social aspects. In contrast, splinter development (e.g. urban sprawl) involves damage to nature and generation of an increasing volume of traffic (these are the main criticisms following a study by Newman and Kenworthy (1989) on the relationship between settlement density and energy consumption). Interestingly, the overly compact city also has this effect as it may generate traffic flows for accessing green and leisure areas, or changes of residence due…