Dipartimento di Fisica - Tesi di Dottorato

Permanent URI for this collectionhttps://lisa.unical.it/handle/10955/35

Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Fisica dell'Università della Calabria.

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    Chiral induction in chromonic materials
    (Università della Calabria, 2023-01-23) Spina, Lorenza; Cipparrone, Gabriella; De Santo, Maria Penelope; Ciuchi, Federica; Bartucci, Rosa
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    Measurements of single, double and triple differential cross-sections of top-quark pair production, in the lepton+jets channel, in pp collisions at Ös=13 TeV using the data collected by the ATLAS detector during the full Run 2.
    (Università della Calabria, 2023-05-03) Curcio, Francesco; Cipparrone, Gabriella; Tassi, Enrico; Faucci Giannelli, Michele
    In this thesis the differential cross-sections for the inclusive production of t t pairs have been measured at a center-of-mass energy of p s = 13 TeV. The data were collected by the ATLAS detector during the period spanning from 2015 to 2018, also known as Run 2, and correspond to an integrated luminosity of 140 fb􀀀1. The top-quark pair events were selected in the lepton (either electron or muon) plus jets channel. The single, double and triple differential cross-sections have been measured as a function of the kinematic variables of the t t system or the hadronically decaying top-quark and extrapolated to the full phase-space. The large amount of t t pairs produced at LHC gives the opportunity to perform stringent tests of pQCD by comparing the measured spectra with the theoretical fixed-order NNLO and Monte Carlo predictions.
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    Photon dynamics in metal insulator anisotropic active and passive systems
    (Università della Calabria, 2023-06-12) Aniket, Patra; Cipparrone, Gabriella; Caligiuri, Vincenzo
    In this thesis, we analyzed the photon dynamics in different metal-dielectric anisotropic structures theoretically as well as experimentally, with and without embedded gain materials. The simplest system is a metal-dielectric bilayer that acts as an open cavity and can support some optical modes, which we call pseudo-cavity modes. This system can be used to study strong light matter interaction, which is demonstrated by placing an optical active material or gain medium on top of the open cavity. Since in such an open cavity structure the gain material is directly accessible to the optical stimulation (for example a pump laser), the photoluminescence from the active material can be straightforwardly enhanced. This open cavity also preserves the polarization state, which enables such structures as polarization dependent optical sources. A Metal-Dielectric-Metal (MDM) structure forms a closed cavity with two reflective metal layers. In recent studies, it has been shown that such structures support epsilon near zero (ENZ) modes, and such vanishing dielectric permittivity triggers numerous intriguing new properties such as: cloaking with negative refractive index, Purcell factor enhancement, energy squeezing and electric levitation, etc. In our work, we fabricated MDM cavities and demonstrated the polariton generation inserting a light emitting gain material inside the dielectric layer. By matching the ENZ cavity resonance with gain medium we obtained strong coupling, and found that the polaritons in this system maintained the ENZ properties of the MDM cavity. In the second part of the work, the photon dynamics in the extreme anisotropic medium are analyzed without an embedded gain medium. With the help of a combined system composed of open and closed cavities, a strong plasmonic PUF (Physical Unclonable Function) has been demonstrated for practical application. With the help of a morphology study of the plasmonic materials and image processing, high-level anticounterfeiting functionality of silver nano island on top of MDM cavities is demonstrated. The photon dynamics in another highly anisotropic system are investigated by combining two different optical resonators, a MDM cavity and a Guided mode resonance (GMR) cavity. The origin of the strong coupling regime occurring in a GMR-MDM architecture has been investigated numerically and experimentally. The role of the polarization of the incident light on the strong coupling between the modes is investigated and plausible applications such as polarization-sensitive switching are discussed.
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    Extreme events: from geophysics to astrophysics
    (Università della Calabria, 2023-07-24) Prete, Giuseppe; Cipparrone, Gabriella; Carbone, Vincenzo
    The aim of this thesis work is the study of extreme event phenomena. Extreme events are well known in nature and they present different characteristics. They are often related to the climate effects, as extreme temperature or rainfall, but it is also possible to define them in the Heliosphere environment, such as slow or fast Coronal Mass Ejection speed events or intense Flares eruptions. Another class of phenomena that can be classified as extreme events are the explosion of Supernova. In this work these different will be analyzed types of phenomena with the help of statistical models, numerical simulations and data analysis. In the first part we will focus on the extreme events that influence the climate. In particular, we study how these phenomena characterize different world regions. In particular we will concentrate on three regions: the Antarctica continent, the Basilicata and the Calabria regions. The study will be made with the help of a statistical analysis applied on the stations data. This will allow us to make a foresting analysis on the examined regions, identifying what are the zones most affected by extreme phenomena, in order to prevent possible disasters such as floods, landslides, droughts. In the second part we will explore the nature of Heliosphere extreme events. In particular we will study a particular class of Coronal Mass Ejections defined as extreme, namely the low speed ones. We will study this category of extreme events with the help of spacecraft data and numerical simulations. Numerical simulations help to do predictions on the SpaceWeather extreme events, because they are able to reproduce a particular event and study how damaging it can be if it has some particular characteristics. Then we will make a comparison between satellite data and numerical results in order to see if the simulation developed is able to reproduce what the spacecraft detects. We will also study the transport properties of energetic particles at the interplanetary shock, analyzing the possible acceleration mechanisms that can influence the particles energization. In the last part of the thesis, we will concentrate on Galactic and extra Galactic extreme events, called Supernova explosions. We will use numerical simulations in order to reproduce the evolution of the Supernova from early stage to the final time of its evolution. We will set a turbulent and dense environment in which it can develop and we will study its evolution with different configurations. Finally we will try to make a visual comparison between numerical results and spacecraft data obtained for the Supernova Remnant SN1006.
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    Self-Assembling Supramolecular, Nanometric and Mesoscaled Materials: Synthesis, Optical and Morphological Characterization
    (Università della Calabria, 2023-05-26) Di Maio, Giuseppe; Cipparrone, Gabriella; La Deda, Massimo
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    Nanofillers doped buckypaper membranes for highly enhanced recovery of pollutants from wastewater
    (Università della Calabria, 2023-03-29) Baratta, Mariafrancesca; Cipparrone, Gabriella; De Filpo, Giovanni
    L’acqua è un bene prezioso, fonte di vita sulla Terra. Sin dalla notte dei tempi, questa minuscola molecola fatta di soli due elementi e tre atomi, ha assistito all’alternarsi di ere geologiche, ha conosciuto epoche e visto lo sviluppo e il declino di civiltà che attorno all’acqua hanno costruito la loro ricchezza e il loro sostentamento. Dall’acqua dipende la vita e attorno all’acqua si è costruita la vita. L’idea che questa risorsa naturale sia sempre stata presente sulla Terra ha fatto credere per molto tempo che essa sia una fonte inesauribile, a cui tutti possono accedere illimitatamente per soddisfare i propri bisogni. Tuttavia, se fino al secolo scorso, il rapporto tra la domanda e l’offerta si è mantenuto pressoché unitario, con l’avvento della civiltà moderna e, dunque, con lo sviluppo economico che ciò ha comportato, si è assistito a un progressivo aumento della disuguaglianza tra questi due termini, con il primo, quello della domanda, che è letteralmente schizzato alle stelle. La richiesta d’acqua da parte della popolazione mondiale, che attualmente ammonta a 8 miliardi, per il soddisfacimento dei propri bisogni quotidiani ha portato, nel corso degli anni, a un enorme consumo di questa risorsa, senza però che la Terra ricevesse nel frattempo un efficiente ricambio di acqua pulita. Non solo, infatti, il consumo d’acqua è notevolmente aumentato, e le risorse del pianeta nel frattempo sono rimaste pressoché uguali, ma gran parte di questa grossa quantità di acqua è stata sprecata e costantemente inquinata. Inquinata da quella stessa popolazione che ne fa domanda, attraverso il rilascio improprio di rifiuti provenienti dagli impianti di scarico di attività connesse con il sostentamento della vita umana, in primis quelle industriali. Stando a quanto riportato dall’ONU all’Assemblea Generale delle Nazioni Unite del luglio 2010, l’acqua è un diritto umano universale e a tutti deve essere garantito l'accesso all'acqua potabile, al fine di prevenire l’insorgere di malattie infettive. Pratiche di igiene e sanificazione sono dunque necessarie e obbligatorie per rimuovere gli inquinanti presenti nelle acque, prima che queste vengano nuovamente introdotte sulla superficie terrestre e giungano poi sulla nostra tavola. A seguito della notevole diversificazione delle attività antropogeniche, gli inquinanti comunemente rinvenuti nelle acque sono molteplici. Si annoverano coloranti, pesticidi, metalli pesanti, farmaci e organismi patogeni come batteri e virus. Accanto a queste “molecole”, una grossa fonte di inquinamento è poi rappresentata dalla presenza di plastiche, il cui consumo negli ultimi decenni è cresciuto in maniera esponenziale. Il seguente lavoro di tesi si propone di sviluppare delle nuove membrane a base di nanotubi di carbonio (CNTs) da impiegare nella rimozione di inquinanti dalle acque mediante processi di fotocatalisi o di assorbimento. Le membrane a base di CNTs, anche note come buckypapers, si presentano come dei fogli sottili, perfettamente autosostenuti, in cui i CNTs sono assemblati formando una vera e propria rete. Le prestazioni di tali membrane dipendono molto dal tipo di CNTs utilizzati (SWNTs o MWNTs); in generale, però, a differenza delle membrane polimeriche attualmente in commercio, esse sono stabili anche ad alte temperature, sono inoltre flessibili, presentano una buona stabilità chimico-fisica e una buona conduttività elettrica. Al fine di migliorare le loro performances, tali membrane sono state dopate con opportune nanoparticelle, introdotte allo scopo di incrementare selettivamente il recupero dei seguenti inquinanti: piombo e cerio, per quanto concerne la categoria dei metalli pesanti, e, per la categoria dei farmaci, le molecole di diclofenac, ketoprofene e naprossene, tutte comunemente impiegate come antinfiammatori. Nell’ottica della degradazione di inquinanti mediante processi fotocatalitici, sono state inoltre sviluppate nuove membrane composite della forma semiconduttore/buckypapers, in cui questi ultimi espletano la funzione di supporto a uno strato fine di semiconduttore depositato sulla loro superficie. In tal caso, una nuova applicazione nella degradazione di coloranti e antinfiammatori è stata rinvenuta per tali membrane, le quali hanno mostrato delle ottime efficienze di rimozione per gli inquinanti investigati.
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    Optical metasurfaces: from reconfigurable polymer-based platforms to sensing applications
    (Università della Calabria, 2024-04-11) Nicoletta, Giuseppe; Cipparrone, Gabriella; Strangi, Giuseppe
    Research is of paramount importance for the well-being and improvement of life, and this is often supported by material research. It is enough to remember that in the past man could greatly improve his own existence by the discovery of stone, and later he could do so by the discovery of bronze and still later iron. Technology today leads us to have increasingly compact devices that are capable of transmitting data as quickly as possible. Among the greatest challenges for scientists is research into materials for microprocessors, optical fibers, and the optimal use of renewable energy sources. The study of light-matter interaction is of fundamental importance since most electromagnetic devices and phenomena originate from it. In this case, the creation of different structures and geometries makes it possible to modify electromagnetic radiation for the intended scientific purposes. Metamaterials offer the possibility to overcome the limits of the physical and chemical properties of materials. With technical processes, it is possible to create structures that show a unique response thanks to their dimensions, which are smaller than the characteristic incident wavelength. One of the most important challenges in the biomedical, environmental, and chemical fields is the biorecognition of analytes in the surrounding environment with high sensitivity and specificity. One possible solution to achieve this goal is to study the change in refractive index that correlates with the specific molecule or biomolecule that needs to be detected in a fluid. The aim of this thesis is to develop an optical approach for various metasurfaces with high sensitivity, which can be used for biosensors and thus for the detection of biological material such as cells, proteins, bacteria etc. Another important aspect is the study of metasurfaces capable of opti-cal reconfiguration by external stimuli, useful to tune the focus of metalenses. This thesis is divided into four chapters, one appendix, and conclusion and perspective. In the first chapter, the concept of chirality is introduced, the interaction between chiral light and chiral matter. The focus is on extrinsic chiral metasurfaces, the study of 3D out-of-plane helices. A modeling study of various helix parameters and an analysis of the modes and their sensitivity have been performed. The second chapter presents Fano Resonance Optical Coating (FROC). After a brief introduction, relevant theoretical references are given. After accurate simulations on the FROCs, several samples were fabricated and analyzed by spectrophotometry and ellipsometry to provide a few applications for these samples. In the third chapter, metalenses supplied by the Capasso group are presented, infiltrated with various liquid crystals according to Cassie-Baxter theory. The purpose is to tune the metasurface to allow in-depth optical investigation. The goal is to tune the metalenses using photonics to excite the gold nanoparticles inside the liquid crystal. In the fourth chapter, a technique is presented for the low-cost reproduction of metalenses, which focus visible light and can be thermally tuned. The goal is to provide materials that do not degrade over time and that retain their properties for focusing. It has been experimentally demonstrated that due to the thermal effect, it is possible to tune the focus of the lens with a shift of 150 μm. In the appendix, we present a metasurface consisting of a polymer matrix containing gold nanoparticles. These substrates are analyzed from a thermoplasmonic point of view, obtaining excellent results useful, for example, for the purification of materials from bacteria. In addition, these membranes are analyzed from the point of view of sensing by stretching. In the second appendix metasurfaces based on the MIMI nanocavities used as a platform for refractive index sensing are presented.
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    Nonlinear processes in general relativity: from vacuum spacetimes to turbulent plasmas near compact objects
    (Università della Calabria, 2023-07-14) Meringolo, Claudio; Cipparrone, Gabriella; Servidio, Sergio
    Strong gravitational fields are well-described by Einstein’s theory of gravity. In the last decades, observational breakthroughs have supported the milestones of general relativity, stimulating increasing scientific activity. Together with observations, numerical relativity became a very important instrument to validate and extend the comprehension of such observations. In the first part of this thesis, we present new results through the full threedimensional (3D) evolution of black holes, in binary- and multiple-body systems. After a brief review of Einstein’s theory and of the "3+1" formalism adopted, we describe the Spectral FIltered Numerical Gravity CodE (SFINGE). This is a numerical code based on the Fourier decomposition, accompanied by different filtering techniques. The accuracy of the model has been validated through standard testbeds, revealing that the filtered pseudo-spectral technique is highly accurate. We evolve black hole dynamics in vacuum conditions and small domains. The gravitational wave signals have been inspected by employing both Fourier and wavelet analyses, showing net differences among the global configurations. We observe strong nonlinear emission in the case of three-black holes, which can be a template for future observational campaigns. Finally, we introduced also the presence of matter in spacetime, presenting some preliminary results of general relativistic hydrodynamics. In the second part of the thesis, we focus on the plasma in the neighboring regions of black holes, by using numerical models for plasmas in trans-relativistic regimes. We present a very comprehensive campaign of two-dimensional (2D) kinetic Particle-In-Cell (PIC) simulations of special-relativistic turbulence by using the Zeltron code. Imposing a realistic mass ratio between electrons and protons, we analyze the energization of electrons, by varying several plasma parameters. The simulations have been designed to cover several regimes of turbulence in the vicinity of compact objects. These results can find application in a wide range of astrophysical scenarios, including the accretion and the jet emission onto supermassive black holes, such as M87* and Sgr A*.
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    Probing the high-energy dynamics of QCD: selected theoretical and phenomenological studies
    (Università della Calabria, 2023-05-04) Fucilla, Michael; Cipparrone, Gabriella; Papa, Alessandro
    The center-of-mass energies available at modern accelerators, such as the Large Hadron Collider (LHC), and at future generation accelerators, such as the Electron-Ion Collider (EIC) and Future Circular Collider (FCC), offer us a unique opportunity to investigate hadronic matter under the most extreme conditions ever reached. In particular, we can access the Regge-Gribov (or semi-hard) limit of QCD, characterized by the scale hierarchy s ≫ {Q2} ≫ Λ2 QCD, where √s is the center-of-mass energy, {Q} a set of hard scales characterizing the process and ΛQCD is the QCD mass scale. In this limit, large logarithmic corrections can affect both parton densities and hard scattering cross sections. The Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach represents the established tool to resum to all orders, both in the leading (LLA) and the next-to-leading (NLA) approximation, these large-energy logarithmic contributions. However, it is well known that at very low values of the Bjorken-x, the density of partons, per unit transverse area, in hadronic wavefunctions becomes very large leading to the so-called saturation effects. The evolution of densities is then described by non-linear generalizations of the BFKL equation. Among these, the most general is represented by the Balitsky-JIMWLK hierarchy of equations, which is needed to describe the scattering of a dilute projectile on a dense target, or also the scattering of two dense systems. The dense system condition can be achieved by a very small-x proton, but is more easily achieved for large nuclei. It is clear that a detailed comparison with experimental data requires precision predictions that can only be achieved in the next-to-leading logarithmic approximation or beyond. We face this task from two different perspectives. On the one hand developing analytical calculations that allow to increase the theoretical accuracy that can be reached in predictions, and on the other, by proposing phenomenological analyzes that can be directly tested experimentally. In particular, within the BFKL approach we calculate the full NLO impact factor for the Higgs production. This is the necessary ingredient to study the inclusive forward emissions of a Higgs boson in association with a backward identified jet. We claim that this result should necessarily supplement pure fixed-order calculations entering in the collinear factorization framework, which cannot be able to describe the entire kinematic spectrum in the Higgs-plus-jet channel. The result can be as well used to describe the inclusive hadroproduction of a forward Higgs in the limit of small Bjorken x. Moreover, using the knowledge of already known impact factors we propose a series of new semi-hard reactions that can be used to investigate BFKL dynamics at the LHC. We investigate all observables used so far to study BFKL, including: total cross sections, azimuthal coefficients, azimuthal distributions and pT -differential distributions. In the context of linear evolution, we consider also the problem of extending BFKL beyond the NLLA. To this aim, we compute the Lipatov vertex in QCD with higher ϵ- accuracy, where ϵ = (D − 4)/2. This ingredient enters the BFKL kernel at next-to-NLA (NNLLA) accuracy. In fact, the NNLLA formulation of BFKL requires not only two and three-loop calculations, but also higher ϵ-accuracy of the one-loop results, for instance, in the part of the kernel containing the product of two one-loop Lipatov vertices. Finally, in the saturation framework, and more specifically in the Shockwave approach, we calculate the diffractive double hadron photo- or electroproduction cross sections with full NLL accuracy. These results are usable to detect saturation effects, at both the future EIC or already at LHC, using Ultra Peripheral Collisions.
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    Black Hole Dynamics from Vacuum Spacetime to Surrounding Turbulent Plasmas
    (Università della Calabria, 2025-04-28) Imbrogno, Mario; Cipparrone, Gabriella; Servidio, Sergio
    The nonlinear behavior of black holes, governed by the Einstein field equations, cou- pled with the turbulent dynamics of plasma in relativistic regimes, constitutes the cornerstone of both general relativity and high-energy astrophysics. In this thesis, we employ advanced numerical simulations and cutting-edge techniques in numer- ical relativity and plasma physics to investigate these extreme systems and probe the intricate nonlinear interactions between black holes and relativistic plasmas. The investigation begins with simulations of black hole systems in vacuum space- times, using the 3+1 formalism to explore both binary and multi-body interactions. The three-body problem is examined by transitioning from Newtonian mechanics to general relativity. In the classical framework, the interactions are modeled in a typ- ically chaotic configuration, identifying extreme gravitational interactions (EGIs) as transients characterized by complex and highly energetic dynamics. We concentrate on selecting these EGIs as initial data for the general relativistic case, performing a series of numerical relativity simulations to establish a comprehensive set of cases. The analysis of three-body black hole dynamics reveals intricate gravitational wave- forms, which are crucial for interpreting observational data and refining detection strategies. Within the 3+1 framework and in the presence of matter, a novel loga- rithmic formulation has been developed to enhance numerical stability in scenarios characterized by steep gradients, such as those found in stellar atmospheres. Pre- liminary applications of this formulation include the propagation of classical sound waves and the study of the Kelvin-Helmholtz instability. In the second part, we perform simulations using the BHAC code within theGRMHD framework to model the accreting plasma flow near black holes. These simulations provide significant insights into the behavior of matter in magnetically dominated regions, such as those surrounding Sgr A* and M87*, bridging theoretical models with observational data and offering new perspectives on high-energy astrophysi- cal processes, including jet formation, accretion mechanisms, and magnetic recon- nection. Our results demonstrate the presence of a strong turbulent cascade that transfers energy from large (inhomogeneous) accretion scales down to smaller (ho- mogeneous) lengths. This process, therefore, may conDue to the cross-scale cascade, our focus ultimately shifts to local plasma be- havior, where we explore fully kinetic plasma turbulence through high-resolution, direct numerical simulations based on the PIC method. These simulations incor- porate realistic mass ratios between particle species, allowing for a detailed exam- ination of particle acceleration mechanisms within plasma turbulence. We observe the formation of long-lived vortices with profiles typical of macroscopic, magneti- cally dominated force-free states. Inspired by the Harris pinch model for inhomo- geneous equilibria, we describe these metastable solutions using a self-consistent kinetic model in a cylindrical coordinate system centered on a representative vortex, starting from an explicit form of the particle velocity distribution function. Turbu- lence is mediated by these long-lived structures, accompanied by transients in which such vortices merge and self-similarly form new metastable equilibria. For future re- search, we plan to broaden the scope of this investigation by including positrons as a third particle species, enabling a more comprehensive analysis of multi-species plasma behavior and elucidating the dominant processes governing energy transfer, particle energization, and the resulting electromagnetic emissions.tinue to kinetic scales, where collisionless, relativistic physics becomes dominant.