Recent technological advances in quantum simulators have proven that synthetic materials are very well suited to study and realise many condensed matter models. However, many of these synthetic systems are characterized by neutral particles that do not couple to real gauge fields. In order to simulate interesting electromagnetic phenomena, such as the topological insulators, or the Landau levels, there is the need for the implementation of artificial gauge fields. In particular, the topological insulators are very interesting both from the point of view of fundamental physics and concrete applications. They are bulk insulating materials that carry a certain number of edge states which are topologically protected against small perturbations of the system. An example of a topological insulator is the integer quantum Hall effect. While there have been many works studying topological physics with quantum artificial systems, little attention was dedicated to the interplay of topology and the purely classical world. Only in the last couple of years, pioneering efforts to encode a non-trivial topology in the dynamical matrix or into the Hamiltonian of a system have proven that the hallmarks of a topological insulator are not the prerogative of quantum mechanics, but can be also observed with a classical system governed by Newton’s equations. The first part of this thesis is therefore based on our studies dedicated to the implementation of a classical analogue of the integer quantum Hall system, by realizing the Harper-Hofstadter model for classical frequency-modulated coupled harmonic oscillators. The achievement of an artificial gauge field allows also for the deeper study of magnetic effects such as Landau levels. In graphene, an inhomogeneous strain of the lattice is equivalent to an artificial pseudo-magnetic field, and the low-energy spectrum shows the formation of relativistic pseudo-Landau levels. The second part of the thesis is therefore focussed on the photonics honeycomb lattice geometry and our theoretical proposal for a configuration based on an intrinsically driven-dissipative system in which to probe the physics of the Landau levels, and especially the spatial structure of their wavefunctions. Finally, we have also studied spin-orbit coupling in a mechanical system of masses and springs induced by pre-tensioned springs that split the longitudinal and transverse couplings in the honeycomb geometry. We have presented the experimental results of a simple mechanical benzene composed of six pendula connected with pre-tensioned springs, to verify that the eigenmodes of this system are well described by our theory in the presence of spin-orbit coupling.

This thesis work is focused on the investigation of a peculiar phenomenon observed in germanium: the formation of a regular network of columnar nanovoids induced by heavy ion and high fluence irradiation at room temperature. This phenomenon can represent a possible way to produce wide nanostructured areas on semiconductor surfaces by a well-established semiconductor technology process such as ion implantation. However, the formation mechanism of this regular network of Ge columnar nanovoids is still under debate. Therefore, the work has been focused on the investigation of the formation mechanisms and on the possible strategies to control the geometry and the composition of these structures, in order to exploit the results for possible technological applications. In particular, ion implantation was carried out using Sn+ ions with the double aim of creating Ge1-xSnx nanostructures and following the depth distribution of the impinging ions. Furthermore, ion implantation through ultra-thin (10-20 nm) films of silicon nitride (SiNx) was investigated as a possible way to impact on nanovoid formation kinetics, prevent ambient contaminations and prevent Sn out-diffusion upon thermal treatments. Firstly, low temperature Sn+ implants were carried out in order to define a recipe to prepare Ge1-xSnx alloy: Ge1-xSnx alloy films with thickness of 15-30 nm were obtained by implanting Sn+ in Ge at liquid nitrogen temperature and subsequent thermal annealing (600 °C for 10 s). High Sn substitutionality, no relevant diffusion, limited surface segregation and excellent crystallinity were achieved, a tin concentration of x=6-7 at.% was reached. Secondly, Ge nanostructures were prepared by high fluence ion implantation at room temperature and then morphologically and chemically characterized, determining that the obtained nanostructures are constituted by Sn-rich Ge. Nanovoids developed under the SiNx film, with reduced oxygen contamination. The first stages of nanovoid formation were observed for samples with and without the SiNx layer. The SiNx layer seems to induce a retarded nanovoid nucleation in terms of threshold fluence, without hindering nanovoid growth. The experimental data were interpreted on the basis of the vacancy clustering theory. SRIM simulations were performed to compare the distributions of point defects and implanted ions at different conditions in the SiNx/Ge stack. These helped to show that the depth distribution of energy deposition is the relevant parameter. Moreover, it was highlighted that both the redistribution in depth of the SiNx atoms and the implanted Sn+ contribute to a lowering of the Ge concentration causing the formation of a layer where nanovoid nucleation does not occur. Taking into account the ion mixing effect including the introduction of Sn, threshold value of the deposited energy was found. The thermal treatments investigated for the Ge1-xSnx alloy thin films were applied on nanostructured samples, causing a dramatic deformation of the nanovoids probably due to a melting temperature decreased by the presence of tin. The investigation of possible technological applications of Ge nanostructures was carried out, in particular in thermoelectric applications, in lithium ion batteries and gas sensors. Several samples were designed and ad-hoc substrates were produced.

Vortex reconnections and interactions play a fundamental role in the dynamics of fluids and turbulent flows, both in the classical and quantum regime. Studying vortices in a clean system like ultracold gases can therefore help, as a bottom-up approach, to understand the physics in a wider context, including superfluid helium, polariton condensates, fluid dynamics and turbulence, neutron stars and cosmological models. So far vortex-vortex interaction was studied in Bose-Einstein condensates either in rotating systems with the observation of regular Abrikosov lattices or in flat condensates across the Berezinskii-Kosterlitz-Thouless transition. In both cases the geometrical constraints allowed to study just a planar interaction among aligned or anti-aligned vortices. The present study instead is carried out in an axisymmetric cigar-shaped Bose-Einstein condensate. Vortices in prolate structures are also known as solitonic vortices. This geometry is especially suitable for investigating vortex interactions. Indeed vortices are oriented perpendicularly to the condensate axis to minimize their length, hence energy, and, because of the cylindrical symmetry, the orientation of a vortex in the radial plane has no constraints. These facts permit interactions to occur with different incoming relative angles between the vortex lines and with different relative velocities. The strong confinement, acting along the radial axis, enhances also interesting effects due to the boundaries.

This study offers a reinterpretation of the direct tradition of medieval Platonism on the basis of new evidence from the Meno and the Phaedo translated into Latin by Henry Aristippus between 1154 and 1160. In particular, it provides an edition of interlinear and marginal annotations and glosses of the Meno and the Phaedo: the manuscript tradition is particularly useful for understanding which aspects of these two Platonic dialogues were particularly studied during the Middle Ages, as it preserves the considerations of various readers on Platonic philosophy. In the most fortunate cases, it is precisely the manuscript tradition that offers new perspectives that can be used to redesign the networks of reception of the two Platonic texts examined in this study in the centuries following their translation, with particular reference to the 13th and 14th centuries. The research was carried out on unpublished material and manuscript testimonies, with the help of two strategies. First, the medieval sources were submetted to a doxographic analysis, through a bottom-up approach consisting in the identification of the terms ‘Plato’, ‘Meno’, ‘Phaedo’ (or ‘Fedrone’ according to medieval usage). This allowed to understand in which contexts and in relation to which themes the references to the three terms appeared and to provide a list of authors who, between the 13th and the 14th century, had the opportunity to read the Meno and/or the Phaedo in Henry Aristippus’ translation. The second strategy, which we could perhaps describe as ‘inside-out’, was applied in the editing phase of the interlinear and marginal annotations and glosses of the two translations. As an especially important paratextual element, the ‘marginal’ writing proves to be particularly useful for deriving the constituent elements of the two dialogues (inside) that were commented, re-written, re-elaborated and interpreted in the margins of the two texts (outside). By employing both strategies, it is possible to reveal the core concepts of Platonic philosophy that, to a greater or lesser extent, caught the attention of medieval readers of the Latin Meno and the Phaedo.

This work shows that it is possible to fabricate phosphate-based planar wave-guides activated by rare earth ions both by sol-gel and RF-sputtering techniques. The objective of this thesis has been to evaluate various methodologies for fab-rication Phosphorous-based planar waveguides. In this context sol-gel and RF-sputtering techniques for planar waveguides fabrication has been investigated. RF-process has been optimized. In case of sol-gel technique a further thermo-dynamical study is required. Each of technique has drawbacks, in sol-gel method the principal question is related to the kinetics of the reaction, since it is too fast, to better control of the reaction rates, and better adjustment of the technological films fabrication, which effects on spectroscopic properties of the waveguiding systems: losses, refractive index. In case of RF-sputtering is no-ticeable that the refractive index is low, and the losses are less than 0.2 dB/cm, however the multicomponent target material increase the complexity of the structure.

The study presented in this thesis is focused on the investigation of Arsenic ultra-shallow distributions in Si for applications as source-drain extension dopant in CMOS technology. Using the Ultra-low energy SIMS measurements the evolution of arsenic shallow distribution was investigated with reference to the metastable electrical activation and the successive deactivation under moderate thermal treatment (550-700°C). Three different approaches to form As USJ were investigated to understand their physical mechanisms to verify their possible application in next generation microelectronics devices. First two activation approaches were based on low energy beamline ion implanted material. The first one is the low temperature (550°C) solid-phase epitaxial re-growth and the second activation approach is a sub-melt laser annealing at different temperatures. A range of deactivation studies was performed using these two classes of material with more attention given to the laser annealed ones. Plasma ion immersion implantation together with the LA was considered as the third approach of arsenic ultra-shallow junction formation. Samples created by AsH3+ plasma were investigated with respect to arsenic distribution, silicon oxide thickness and arsenic local order using SIMS, INAA, and EXAFS analysis.

As its title announces, the general aim of this doctoral thesis is to investigate the growth and use of nanostructured materials in order to make them suitable for sensoristics. Sensors applications have become very important in the last years because of a new sensibility towards pollution of the urban world and its effects on human health. Only very recently people and countries discovered the importance of environment preservation and monitoring. After a period of fast and uncontrolled industrial progress, we are now aware of this danger. Thus we need to monitor the environment and the changes which are happening directly or indirectly because of human presence. During the last decades, solid-state gas sensors have played an important role in environmental monitoring and chemical process control. The strong investigation which followed, made clear that the field of science and sensor technology cannot search for new sensor materials which are ideal, because different applications (e.g. different transformations of energy and different goals for sensors) require different materials. However materials are important drivers in sensor technology. The combination of the right materials (new or existing) to the right application can result in smarter, cheaper, or more reliable sensors. In order to give a contribution to this important evolving situation, during these three years the PhD candidate investigated two of the most important areas related to nanostructured materials used in sensing applications. On one side, the recent interesting field of metal oxide nanowires has been studied, both in terms of fundamentals (growth mechanism and structural properties) and sensor properties towards different gases. On the other side, the less exploited (in terms of sensor devices) field of organic thin films has been investigated, in terms of growth and fundamental properties (charge carriers mobility) which are required to use them as sensors. While nanostructured metal oxides are already in use in commercial sensors (usually in the form of porous thick or thin films), organic materials are still in a prototypal phase, and need further investigation in order to be effectively used. This different evolution step is reflected also in the present thesis: in which zinc and tin oxide nanowires are characterized as gas sensing devices, while molecular materials are only optimized towards a better order and a higher carrier mobility, which is one of the bottlenecks towards a higher response. For this reason, the chapters concerning metal oxide nanowires will give a wide picture, from their growth mechanism to their structure until their use (in different architectures) in sensing applications. Oxide nanowires have been used as passive (resistive) sensors (they have been used also as active sensors, but such data are still under analysis) both in order to develop new real sensors, and to better understand the sensing mechanism behind the high response of such nanostructured materials. Their nanoscale dimensions, comparable to the depletion layer, makes them almost ideal intrinsic on-off devices, and this can be exploited to fabricate a new generation of sensors characterized by a huge response. The problems of metal oxide sensors are however their poor selectivity and high working temperature. In this direction goes the investigation of the molecular materials. Concerning the organic complement in this thesis, the aim of the experimental work was the optimization of the overall field effect mobility of carriers (holes) along the whole device, which means several microns (tens of microns, due to the impossibility to use standard lithography techniques on organic delicate materials). This meant the minimization of grain boundaries, that are one of the steps hindering the charge carrier mobility, and even the recently found domain boundaries. Exploiting the high kinetic energy achievable by SuMBD, we found that it is partially transformed in surface mobility, increasing the order of the fundamental building blocks inside each monolayer, and decreasing the grain and domain boundary density (because of wider and less fractal grains). At the end of the thesis we will show a first combination of the two families of materials, just as a sample of what the exploitation of the best features of each family (high response for metal oxides and good selectivity for organic materials) can provide.

In this thesis we investigate the properties of impurities immersed in a dilute Bose gas at zero temperature using quantum Monte-Carlo methods. The interactions between bosons are modeled by a hard sphere potential with scattering length a, whereas the interactions between the impurity and the bosons are modeled by a short-range, square-well potential where both the sign and the strength of the scattering length b can be varied by adjusting the well depth. We calculate the binding energy, the effective mass and the pair correlation functions of a impurity along the attractive and the repulsive polaron branch. In particular, at the unitary limit of the impurity-bosons interaction, we find that the binding energy is much larger than the chemical potential of the bath signaling that many bosons dress the impurity thereby lowering its energy and increasing its effective mass. We characterize this state by calculating the bosons-boson pair correlation function and by investigating the dependence of the binding energy on the gas parameter of the bosonic bath. We also investigate the ground-state properties of M impurities in a Bose gas at T=0. In particular, the energy and the phase diagram by using both quantum Monte-Carlo and mean field methods.

Si tratta di un'indagine approfondita circa il concetto di Eingedenken" che Walter Benjamin utilizza nei suoi scritti dal 1927 fino alla morte (nel 1940)."

Atomistic simulations based on Molecular Dynamics (MD) were used to model the lattice distortions in metallic nano-polycrystalline microstructures, with the purpose of supporting the analysis of the X-ray powder diffraction patterns with a better, atomic level understanding of the studied system. Complex microstructures were generated with a new modified Voronoi tessellation method which provides a direct relation between generation parameters and statistical properties of the resulting model. MD was used to equilibrate the system: the corresponding strain field was described both in the core and in surface regions of the different crystalline domains. New methods were developed to calculate the strain tensor at the atomic scale. Line Profile Analysis (LPA) was employed to retrieve the microstructure information (size and strain effects) from the powder diffraction patterns: a general algorithm with an atomic level resolution was developed to consider the size effects of crystalline domains of any arbitrary shape. The study provided a new point of view on the role of the grain boundary regions in nano-polycrystalline aggregates, exploring the interference effects between different domains and between grain boundary and crystalline regions. Usual concepts of solid mechanics were brought in the atomistic models to describe the strain effects on the powder diffraction pattern. To this purpose the new concept of Directional - Pair Distribution Function (D-PDF) was developed. D-PDFs calculated from equilibrated atomistic simulations provide a representation of the strain field which is directly comparable with the results of traditional LPA (e.g. Williamson-Hall plot and Warren-Averbach method). The D-PDF opens a new chapter in powder diffraction as new insights and a more sound interpretation of the results are made possible with this new approach to diffraction LPA.