Table of contents

Young Researcher Meeting, Torino 2016

F Agostini, C Antolini, A Avella, G Cattani, R Cuccaro, A Cultrera, M Di Stefano, G Fragione, L Lolli, M Migliaccio, L Pagnanini, E Pessana, F Piacentini, D Pietrobon, E Pusceddu, R Romeo, M Serra, E Simonetto, F Stellato

Preface

The Young Researcher Meeting (www.yrmr.it) has been established as a forum for students, postdoctoral fellows and young researchers determined to play a proactive role in the scientific progress. Since 2009 we run itinerant yearly meetings to discuss the most recent developments and achievements in Physics, as we are firmly convinced that sharing expertise and experience is the foundation of the research activity. One of the main purposes of the conference is actually to create an international network of young researchers, both experimentalists and theoreticians, and fruitful collaborations across the different branches of Physics.

The format we chose is an informal meeting primarily aimed at students and researchers at the beginning of their scientific career, who are encouraged to present their work in brief presentations able to provide genuine engagement of the audience and cross-pollination of ideas.

The 7^th edition of the Young Researcher Meeting was held at the Istituto Nazionale di Ricerca Metrologica (INRiM) in Turin, the Italian National Metrology Institute responsible for the national standards of the International System of Units.

The conference took place from Monday 24^th to Wednesday 26^th October 2016. This edition gathered 120 participants belonging to universities and research centres from all over the world. The plenary talk sessions covered several areas of pure and applied Physics, and they were complemented by an extremely rich and interactive poster session, which was also extended to the coffee breaks.

The programme included a "poster & wine" session on the first evening, a guided tour at the Turin Astrophysical Observatory and a very enjoyable and friendly conference dinner in a typical Piedmont-cuisine restaurant. The participants had furthermore the unique opportunity to visit the INRiM laboratories, which host a wide spectrum of Physics experiments. This year's edition of the meeting featured a lectio magistralis by Walter Bich¹, entitled "Metrology, why not?", which provided an all-around picture of the connections between metrology and several other physics-related research fields. Three invited speakers (Dr. E. Palazzi², Prof. F. Sciarrino³, and Dr. A. Giachero⁴), with different scientific backgrounds, kindly accepted to give broad-audience talks pertaining their research fields (Dr. A. Giachero also contributed to this publication).

This edition of the Young Researcher Meeting gave the organisers the opportunity to present to the attendees, and officially launch, two projects of interest for the wide scientific community:

ⅳ the recently established International Physicists Network (IPN)⁵, an Italian non-profit association having the main purpose to create and promote an international network of young researchers in Physics, both experimental and theoretical, in order to initiate collaborations between different branches of Physics. IPN will be responsible for running the organisation of the YRM in the coming years, as it is the natural continuation of an almost decade-long collaboration between the funders and organisers of the YRM;

ⅳ the partnership code-named Dandelion with the Consortium for Technology Transfer (C2T) and specifically with its top-tier service designed for professional researchers, Find Your Doctor (FyD). Dr. Eva Ratti⁶ gave the talk "What meaning for a PhD nowadays? Knowledge workers as a drive for change" to introduce FyD goals and methods to help researchers to connect with companies looking for their expertise. The project Dandelion has been presented during the "poster & wine" session. It aims to "let competences, ideas, resources and company requirements meet together in an online/offline shared area and exploit the best of both sides" adding a bottom-up approach where "young researchers can now submit their own ideas and research/application projects directly to possible interested companies". It is mainly based on the Elevator Pitch paradigm, complementary to the traditional top-down approach where companies advertise their openings/research challenges and the interested candidates submit their proposals.

This volume consists in a selection of the contributions presented at the conference as either talks or posters. These cover topics in astrophysics and cosmology, particle and theoretical physics, soft and condensed matter, medical physics, quantum information and quantum technologies, and of course metrology.

Organising and Editorial Committee

Fabio Agostini

(fabioagostini31@gmail.com)

NAIS

Alessio Avella

(a.avella@inrim.it)

INRiM

Rugiada Cuccaro

(r.cuccaro@inrim.it)

INRiM

Marco Di Stefano

(marco.distefano@cnag.crg.eu)

Centre Nacional d'Anàlisi Genòmica - Centre de Regulació Genòmica (CNAG-CRG)

Lapo Lolli

(l.lolli@inrim.it)

INRiM

Lorenzo Pagnanini

(lorenzo.pagnanini@gssi.infn.it)

Gran Sasso Science Institute

Fabrizio Piacentini

(f.piacentini@inrim.it)

INRiM

Emanuela Pusceddu

(emanuela.pusceddu@gmail.com)

National Research Council-CNR

Matteo Serra

(matteoserra83@gmail.com)

Claudia Antolini

(cla.antolini@gmail.com)

Giordano Cattani

(giordano.cattani@gmail.com)

Alessandro Cultrera

(a.cultrera@inrim.it)

INRiM

Giacomo Fragione

(giacomo.fragione90@gmail.com)

Hebrew University of Jerusalem

Marina Migliaccio

(migliaccio@asdc.asi.it)

ASDC – ASI Science Data Center

Enrica Pessana

(e.pessana@inrim.it)

INRiM

Davide Pietrobon

(daddeptr@gmail.com)

Raffaella Romeo

(r.romeo@inrim.it)

INRiM

Enrico Simonetto

(e.simonetto@inrim.it)

INRiM

Francesco Stellato

(francesco.stellato@roma2.infn.it)

INFN Roma Tor Vergata

Silvia Cavallero

(Local Organising Committee)

(s.cavallero@inrim.it)

INRiM

Acknowledgements

The organisers of the 7^th Young Researcher Meeting, held in Torino, would like to thank all the authors for their scientific contributions and all the people who made this conference smooth and pleasant.

We thank the Istituto Nazionale di Ricerca Metrologica (INRiM) for hosting the conference. INRiM and the commercial sponsors (Anton Paar, CalRef, Crisel Instruments, ID Quantique, LOT-Quantum Design, Pfeiffer Vacuum, Sistemi HS, Tele-dyne-Lecroy) for covering the organisational costs, the expenses for the publication of the proceedings, and providing travel grants to selected speakers.

We are grateful to Dr. W. Bich for filling his lecture with his contagious enthusiasm, Dott. Alberto Cora (and his colleagues) at the Istituto Nazionale di Astrofisica enrolled at the Astrophysical Observatory of Pino Torinese for the interesting guided tours. Many thanks also to the colleagues at INRiM who guided the extensive tour of the laboratories.

The event was broadcast live on the conference website, and the recordings are available on YRM Youtube channel at http://www.youtube.com/c/YoungResearcherMeeting.

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The search for the B-mode polarization of Cosmic Microwave Background (CMB) is the new frontier of observational Cosmology. A B-mode detection would give an ultimate confirmation to the existence of a primordial Gravitational Wave (GW) background as predicted in the inflationary scenario. Several experiments have been designed or planned to observe B-modes. In this work we focus on the forthcoming Large Scale Polarization Explorer (LSPE) experiment, that will be devoted to the accurate measurement of CMB polarization at large angular scales. LSPE consists of a balloon-borne bolometric instrument, the Short Wavelength Instrument for the Polarization Explorer (SWIPE), and a ground-based coherent polarimeter array, the STRatospheric Italian Polarimeter (STRIP). SWIPE will employ a rotating Half Wave Plate (HWP) polarization modulator to mitigate the systematic effects due to instrumental non-idealities. We present here preliminary forecasts aimed at optimizing the HWP configuration.

Short baseline laboratory (SBL) anomalies have shown preference for light sterile neutrinos with eV masses. These particles, if confirmed, would be produced in the early universe and would add their contribution to the relativistic energy density basically increasing the effective number of extra relativistic species (N_eff). It has been shown that when the matter potential produced by the sterile interactions becomes smaller than the vacuum oscillation frequency, sterile neutrinos are plentifully produced by the scattering effects in the sterile neutrino sector. This behaviour, however, leads to a ΔN_eff ≃ 1 which is in tension at 3 − 5σ with the actual constraints given by the latest Cosmic Microwave Background radiation (CMB) observations. In order to avoid the thermalization of eV sterile neutrinos in the early universe, secret interactions between the sterile and active sectors mediated by a massive vector boson (M_X < M_W) have been proposed. In particular, interactions mediated by a gauge boson having M_X < 10 MeV would suppress the sterile neutrino production for T > 0.1 eV and seem to save the cosmological constraints coming from big-bang nucleosynthesis (BBN) and mass bounds. In this framework, cosmological observations represent a powerful tool to constrain neutrino physics complementary to laboratory experiments. In particular, observations of the CMB have the potential to constrain the properties of relic neutrinos, as well as of additional light relic particles in the universe. In this work we present the effects of the strength of the interaction on the neutrino fluid perturbations and on the CMB anisotropies power spectrum.

Fabry-Pérot interferometers are commonly used as tunable filters in a variety of scientific fields. We here consider the use of a single Fabry-Pérot as a universal tunable filter in hyperspectral imaging applications, when it is necessary to recover image information of the scientific target at different wavelengths.

Fabry-Pérot are commonly used to scan small portions of the spectrum, defined by suitable prefilters. This is necessary due to the multi-peak response of a single interferometer. In order to overcome this issue we propose a novel triple-pass configuration, able to provide a fast and continuous sampling of the electromagnetic spectrum in the visible-infrared range without the need for a collection of dedicated prefilters.

In this work we describe a possible way to use X-ray and microwave observations of nearby galaxy clusters to derive the value of the Hubble constant, that parametrises the expansion rate of the Universe. We provide a brief introduction to the Sunyaev-Zel'dovich effect that allows to detect galaxy clusters at microwave frequencies, and the method to combine it with X-ray observables. We emphasize what kind of considerations should be done when applying the method on real data and study the effect of the geometry of the clusters on the final result.

The study of the polarization of faint diffuse synchrotron sources, named radio halos, found in some galaxy clusters, is of paramount importance to characterize large scale magnetic fields. This is an hard task with the current radio telescopes but a next generation radio interferometer, the Square Kilometre Array (SKA), could help to shed light on the origin of cosmic magnetism. Thanks to its sensitivity, its broader bandwidth and its resolution, the SKA will allow us to perform complete and accurate studies of magnetic fields in clusters. In order to explore the potentiality of the SKA, we used state-of-art magneto-hydro-dynamical numerical simulations to produce synthetic maps of radio halos, taking into account the expected performances of the SKA1-MID in the radio band from 350 to 1050 MHz. Starting from the resulting maps, we were able to verify that radio halos could be intrinsically polarized and that SKA1-MID could detect their polarization, crucial to constraining the properties of large scale magnetic fields.

High energy cosmic ray electrons and positrons probe the local properties of our galaxy. In fact, regardless of the production mechanism, electromagnetic energy losses limit the typical propagation scale of GeV-TeV electrons and positrons to a few kpc. In the diffusion model, the presence of nearby and dominant sources may produce an observable dipole anisotropy in the cosmic ray fluxes. We present a detailed study on the role of anisotropies from nearby sources in the interpretation of present cosmic ray electron and positrons fluxes. Predictions for the dipole anisotropy from known astrophysical sources as Supernova Remnants (SNRs) and pulsars taken from the Green and the Australia Telescope National Facility (ATNF) catalogs are shown. The results are obtained from models compatible with the most recent AMS-02 data on electrons and positrons fluxes. In particular, anisotropies for single sources as well as for a distribution of catalog sources are discussed. We compare our results with current anisotropy upper limits from the Fermi-LAT and PAMELA experiments, showing that the search of anisotropy in the electron and positron fluxes represents a complementary tool to inspect the properties of close SNRs, as for example the Vela SNR.

We forecast the future constraints on scale-dependent parametrizations of galaxy bias and their impact on the estimate of cosmological parameters from the power spectrum of galaxies: in our approach we perform a Fisher matrix analysis with two different parametrizations of scale-dependent bias. The two main results obtained from the analysis are: first, allowing for a scale-dependent bias does not significantly increase the errors on the other cosmological parameters apart from the rms amplitude of density fluctuations, σ₈, and the growth index γ, whose uncertainties increase by a factor up to two, depending on the bias model adopted. Second, we find that the accuracy in the linear bias parameter b0 can be estimated to within 1-2% at various redshifts regardless of the fiducial model. The non-linear bias parameters have significantly large errors that depend on the model adopted.

It has been found that large-scale anisotropies in the Cosmic Microwave Background are anomalous with respect to the predictions of the standard model of cosmology. We focused on the low multipole alignments, assuming the ΛCDM model and we confirmed that the quadrupole/octupole and the dipole/quadrupole/octupole alignments are anomalous with a significance up to 99.9%, for both WMAP and Planck data. Trying to explain the origin of this kind of anomalies we tested the dipolar model. This alternative phenomenological model explains the CMB hemispherical power asymmetry found in the WMAP and Planck data, so is possible that it can solve also other CMB directional anomalies. We show that the alignments are anomalous in the dipolar model too, roughly at the same level as in ΛCDM. We conclude that the dipolar model does not provide a better fit to the data than the ΛCDM.

Challenging issues in treatment planning system for hadrontherapy are the accurate and fast calculation of dose distribution, the reduction in memory space required to store the dose kernel of individual pencil beams and the shortening of computation time for dose optimization and calculation. In this framework, the prediction of lateral dose distributions is a topic of great interest because currently the double gaussian parametrization is typically used as approximation although other parameterizations are also available. The best accuracy for this kind of calculations can be obtained by Monte Carlo methods, at the expense of a long computing time. This work aims to present a flexible computational model for the calculation of the lateral profile of a pencil proton beam and the results of its implementation in a treatment planning system. The model calculation are compared with the currently used double gaussian approximation and the Monte Carlo calculations, and the tests are performed in water and in presence of inhomogeneities.

Superparamagnetic iron oxide nanoparticles have recently been investigated for their potential to kill cancer cells with promising results, owing to their ability to be targeted and heated by magnetic fields. In this study, novel hydrogel, chitosan Fe₃O₄ magnetic nanoparticles were synthesized to induce magnetic hyperthermia, and targeted delivering of chemotherapeutics in the cancer microenvironment. The characteristic properties of synthesized bare and CS-MNPs were analyzed by various analytical methods: X-ray diffraction, Fourier transformed infrared spectroscopy, Scanning electron microscopy and Thermo-gravimetric analysis/differential thermal analysis. Magnetic nanoparticles were successfully synthesized using the co-precipitation method. This synthesis technique resulted in nanoparticles with an average particle size of 16 nm. The pure obtained nanoparticles were then successfully encapsulated with 4-nm-thick chitosan coating. The formation of chitosan on the surface of nanoparticles was confirmed by physicochemical analyses. Heating experiments at safe magnetic field (f = 100 kHz, H =10-20 kA m^-1) revealed that the maximum achieved temperature of water stable chitosan-coated nanoparticles (50 mg ml^-1) is fully in agreement with cancer therapy and biomedical applications.

The quality assurance of particle therapy treatment is a fundamental issue that can be addressed by developing reliable monitoring techniques and indicators of the treatment plan accuracy. Monitoring using Position Emission Tomography (PET) systems is the only in-vivo non invasive technique employed clinically and has been carried out in particle therapy since 1997. However, the PET monitoring of β⁺ emitter isotopes is typically done after the treatment, resulting in a large fraction of lost data because of the isotopes rapid physical decay. The INSIDE collaboration has recently installed an in-beam PET scanner at the Italian National Center of Oncologic Hadrontherapy in Pavia, Italy. Here, there is an ongoing project in order to start testing the method on patients. This work focuses on the online performances of the scanner with clinical beams.

Breast cancer is one of the most frequent tumours in women. During the '90s, the introduction of screening programmes allowed the detection of cancer before the palpable stage, reducing its mortality up to 50%. About 50% of the women aged between 30 and 50 years present dense breast parenchyma. This percentage decreases to 30% for women between 50 to 80 years. In these women, mammography has a sensitivity of around 30%, and small tumours are covered by the dense parenchyma and missed in the mammogram. Interestingly, breast-specific gamma-cameras based on semiconductor CdZnTe detectors have shown to be of great interest to early diagnosis. Infact, due to the high energy, spatial resolution, and high sensitivity of CdZnTe, molecular breast imaging has been shown to have a sensitivity of about 90% independently of the breast parenchyma. The aim of this work is to determine the optimal combination of the detector pixel size, hole shape, and collimator material in a low dose dual head breast specific gamma camera based on a CdZnTe pixelated detector at 140 keV, in order to achieve high count rate, and the best possible image spatial resolution. The optimal combination has been studied by modeling the system using the Monte Carlo code GATE. Six different pixel sizes from 0.85 mm to 1.6 mm, two hole shapes, hexagonal and square, and two different collimator materials, lead and tungsten were considered. It was demonstrated that the camera achieved higher count rates, and better signal-to-noise ratio when equipped with square hole, and large pixels (> 1.3 mm). In these configurations, the spatial resolution was worse than using small pixel sizes (< 1.3 mm), but remained under 3.6 mm in all cases.

Lung cancer is one of the most lethal types of cancer, because its early diagnosis is not good enough. In fact, the detection of pulmonary nodule, potential lung cancers, in Computed Tomography scans is a very challenging and time-consuming task for radiologists. To support radiologists, researchers have developed Computer-Aided Diagnosis (CAD) systems for the automated detection of pulmonary nodules in chest Computed Tomography scans. Despite the high level of technological developments and the proved benefits on the overall detection performance, the usage of Computer-Aided Diagnosis in clinical practice is far from being a common procedure. In this paper we investigate the causes underlying this discrepancy and present a solution to tackle it: the M5L WEB- and Cloud-based on-demand Computer-Aided Diagnosis. In addition, we prove how the combination of traditional imaging processing techniques with state-of-art advanced classification algorithms allows to build a system whose performance could be much larger than any Computer-Aided Diagnosis developed so far. This outcome opens the possibility to use the CAD as clinical decision support for radiologists.

For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

Nowadays atomic optical lattice clocks can perform frequency measurements with a fractional uncertainty at the 10^-18 level in few hours of measurement, outperforming the best caesium (Cs) standards operated in the world. Since the definition of the unit of time is based on Cs, a worldwide debate about the need to promote the redefinition of the second on a optical reference is under-way. At INRIM (Istituto Nazionale di Ricerca Metrologica) we developed an optical lattice clock based on ytterbium atoms and compared it against a Cs fountain. These results are an important contribution to the debate.

We apply the bosonization technique to derive the phase diagram of a balanced unit density two-component dipolar Fermi gas in a one dimensional lattice geometry. The considered interaction processes are of the usual contact and dipolar long-range density-density type together with peculiar correlated hopping terms which can be generated dynamically. Rigorous bounds for the transition lines are obtained in the weak coupling regime. In addition to the standard bosonization description, we derive the low energy phase diagram taking place when part of the interaction is embodied non-perturbatively in the single component Hamiltonians. In this case the Luttinger liquid regime is shown to become unstable with respect to the opening of further gapped phases, among which insulating bond ordered wave and Haldane phases, the latter with degenerate edge modes.

The flow fields which can be observed inside several components of aerospace propulsion systems are characterised by the presence of very localised phenomena (boundary layers, shock waves,...) which can deeply influence the performances of the system. In order to accurately evaluate these effects by means of Computational Fluid Dynamics (CFD) simulations, it is necessary to locally refine the computational mesh. In this way the degrees of freedom related to the discretisation are focused in the most interesting regions and the computational cost of the simulation remains acceptable. In the present work, a discontinuous Galerkin (DG) discretisation is used to numerically solve the equations which describe the flow field. The local nature of the DG reconstruction makes it possible to efficiently exploit several adaptive schemes in which the size of the elements (h-adaptivity) and the order of reconstruction (p-adaptivity) are locally changed. After a review of the main adaptation criteria, some examples related to compressible flows in turbomachinery are presented. An hybrid hp-adaptive algorithm is also proposed and compared with a standard h-adaptive scheme in terms of computational efficiency.

In this study, liquid plasma treatment was used to improve the morphology of Poly-є-CaproLactone (PCL) NanoFibers (NFs), followed by performing a Dielectric Barrier Discharge (DBD) plasma surface modification to enhance the hydrophilicity of electrospun mats generated from plasma-modified PCL solutions. Cell interaction studies performed after 1 day and 7 days clearly revealed the highly increased cellular interactions on the double plasma-treated nanofibers compared to the pristine ones due to the combination of (1) a better NF morphology and (2) an increased surface hydrophilicity.

The thermodynamics of a qubit undergoing dephasing due to the coupling with the external environment is discussed. First of all, we assume the dynamics of the system to be described by a master equation in Lindblad form. In this framework, we review a standard formulation of the first and second law of thermodynamics that has been known in literature for a long time. After that, we explicitly model the environment with a set of quantum harmonic oscillators choosing the interaction such that the global dynamics of system and bath is analytically solvable and the Lindblad master equation is recovered in the weak-coupling limit. In this generalized setting, we can show that the correlations between system and bath play a fundamental role in the heat exchange. Moreover, the internal entropy production of the qubit is proven to be positive for arbitrary coupling strength.

Investigation of ferrofluids nanostructure by the laser light scattering technique is presented. Experimental studies involved measurements of the intensity of the laser radiation scattered by ferrofluid particles in interaction with albumin and under the influence of magnetic field. The effects of the magnitude and duration of the applied magnetic field on the formation of aggregates of magnetic nanoparticles and also the influence of magnetic fluids of different concentrations on blood proteins are considered. The findings may be useful for medical applications.

In this paper we present a general theoretical framework to study interacting electrons under the influence of an external time-periodic driving, such as a homogeneous laser field. This is performed through a true many-body calculation and the use of Floquet theory. In particular, we consider a linear atomic chain using the Hubbard model to describe the short-ranged Coulomb interactions between electrons, plus Cluster Perturbation Theory to embed the many-body exact solution for a finite system into both an extended and an infinite lattice. Due to the presence of the external time-periodic perturbation, the electronic problem can be mapped into the study of photon-dressed quasiparticles thanks to Floquet theorem, keeping into account of all the virtual processes (absorption and emission of photons by electrons) with the laser field. This leads to an extension of the many-body static theories to out-of-equilibrium systems. This theoretical approach allowed us to show how the electronic properties of the system can be controlled and tuned varying the laser parameters. Above all, an inverse insulator-to-metal transition can be obtained for the one dimensional infinite lattice, and edge localized states appear as a finite size effect in an extended truncated chain.

Ion Cyclotron Resonance Heating and Current Drive is a method that has the ability to heat directly the ions in the Deuterium-Tritrium fuel to the high temperature needed for the fusion reaction to works. The capability of efficiently couple the Radio Frequency power to the plasma plays a big role in the overall performance of a fusion device. A Traveling Wave Antenna in a resonant ring configuration is a good candidate for an Ion Cyclotron Resonance Heating and Current Drive system. It has the capability to increase the coupled power with respect to present designs and to have a highly selective power spectrum that can be peaked around the maximally absorbed wave. It is also insensitive to the loading variations due to fluctuation of the plasma edge increasing the reliability and the efficiency of the system. It works as a low power density launcher due to the possible large number of current carrying elements.

The AMADEUS collaboration studies low-energy K⁻ interactions with light nuclei in order to clarify some aspects related to the behaviour of hadrons containing strangeness in nuclear medium. One of the main topics is the quest about the possible formation of Kaonic Nuclear Clusters (KNC), which depends on the strength of the anti-kaons interaction with nucleons. In kaonic absorption experiments, the search for KNC is strictly connected with the measurement of the yields of the so-called multi-nucleon absorption processes. In this paper, the study of Σ⁰p correlated production from K⁻ absorption in ¹²C, using the KLOE 2004-2005 data set, is reported. The yield of the two nucleon absorption (2NA), when the produced Σ⁰ and p particles are free from any final state interaction process, was measured for the first time. The contribution of a ppK⁻ bound state was also tested. The best fit is obtained for a ppK⁻ state with a binding energy of 45 MeV and a width of 30 MeV, but the statistical significance is at the level of 1σ only.

In this paper new ideas to experimentally investigate the issues of chiral symmetry restoration and the first order phase transition in the region of moderate-large baryon density of the phase diagram of strongly interacting matter are presented. The experimental strategy to address these points is to use a new fixed-target experiment at the CERN SPS (Super Proton Synchrotron) dedicated to the measurement of the production of muon pairs with unprecedented precision. Dileptons offer the possibility to measure temperature to obtain a caloric curve and to probe chiral symmetry restoration by studying for the first time the mass modifications in a simultaneous measurement of the vector meson ρ and its axial vector partner a₁.

The ^archPbMoO₄ scintillating crystal has been produced from archaeological lead for the first time. The advanced technique for deep purification of lead against chemical impurities was used resulting in 99.9995% purity level of final material. The ^archPbMoO₄ crystal was characterized by means of cryogenics bolometric measurements and demonstrates excellent performances as a scintillating bolometer. The energy resolution (0.3% at 1462 keV of ⁴⁰K), the high light yield (5.2 keV/MeV for γs, and 1.2 keV/MeV for α particles) and the highly efficient particle identification achieved with this detector, representing the high quality of the crystal. As a final proof for the feasibility of the ^archPbMoO₄ crystal as a promising detector to search for the neutrinoless double β-decay of ¹⁰⁰Mo, the crystal should be produced using the LTG Czochralski technique to prevent the possible contamination during the crystal growth and to increase the production yield.

A complete understanding of neutrinos properties requires a study and a characterization of the interactions of the daughter particles created in a neutrino-nucleus interaction. The Liquid Argon In A Testbeam (LArIAT) experiment is a small-scale liquid argon detector situated in the Fermilab Test Beam Facility. The LArIAT experiment is exposed to a tertiary beam comprised of mostly pions along with a mix of muons, protons, kaons, and electrons. LArIAT's goal is to characterize the response of the Liquid Argon Time Projection Chamber (LArTPC) to known incoming charged particles and measure their interactions in Argon, in order to understand their cross-sections and to help developing and tuning simulations and reconstruction algorithms for LArTPC neutrino experiments. The world's first measurement of a pion cross-section on an Argon target, made with the LArIAT detector, is presented here.

Thanks to oscillation experiments it is now an established fact that neutrinos are massive particles. Yet, the assessment of neutrinos absolute mass scale is still an outstanding challenge in particle physics and cosmology as oscillation experiments are sensitive only to the squared mass differences of the three neutrino mass eigenstates. The mass hierarchy is not the only missing piece in the puzzle. Theories of neutrino mass generation call into play Majorana neutrinos and there are experimental observations pointing toward the existence of sterile neutrinos in addition to the three weakly interacting ones. Three experimental approaches are currently pursued: an indirect neutrino mass determination via cosmological observables, the search for neutrinoless double β-decay, and a direct measurement based on the kinematics of single β or electron capture decays.

Bolometers and calorimeters are low temperature detectors used in many applications, such as astrophysics, fast spectroscopy and particle physics. In particular, sensitive calorimeters play an important role in the neutrino mass measurement and in the search for the neutrinoless double β-decay. There has been great technical progress on low temperature detectors since they were proposed for neutrino physics experiments in 1984. This general detector paradigm can be implemented in devices as small as a micrometer for sub eV radiation or as large as 1 kg for MeV scale particles. Today this technique offers the high energy resolution and scalability required for leading edges and competitive experiments addressing the still open questions in neutrino physics.

The occurrence of ice-nucleating aerosols in the atmosphere has a profound impact on the properties of clouds, and in turn, influences our understanding on weather and climate. Research on this topic has grown constantly over the last decades, driven by advances in online and offline instruments capable of measuring the characteristics of these cloud-modifying aerosol particles. This article presents different aspects to the understanding of how aerosol particles can trigger the nucleation of ice in clouds. In addition, we present some experimental results obtained with the Dynamic Filter Processing Chamber, an off-line instrument that has been applied extensively in the last years and that circumvents some of the problems related to the measurement of Ice Nucleating Particles properties.

Terrestrial gamma-ray flashes are brief submillisecond gamma-ray emissions, produced during thunderstorms and strictly correlated to lightning and atmospheric electric activity. Serendipitously discovered in 1994 by the Compton Gamma Ray Observatory, these elusive events have been further investigated by several missions and satellites devoted to high-energy astrophysics, such as RHESSI, AGILE and Fermi. Terrestrial gamma-ray flashes are thought to be bremsstrahlung gamma-rays, produced at the top of thunderclouds by avalanches of electrons accelerated within thunderstorm strong electric fields and abruptly braked in the atmosphere. Exhibiting energies ranging from few keV up to several tens of MeV, terrestrial gamma-ray flashes are the most energetic phenomenon naturally occurring on Earth and they can represent a severe risk for airplanes and aircraft transports, both for the crew and the on board electronics, that should be carefully investigated and understood.

The AGILE (Astrorivelatore Gamma ad Immagini LEggero) satellite is an entirely Italian mission, launched in 2007 and still operational, aimed at investigating gamma-ray emissions from cosmic sources. The wide energy range and the unique submillisecond trigger logic of its on-board instruments, together with the narrow quasi-equatorial orbit of the spacecraft, make AGILE a very suitable instrument to detect and investigate terrestrial gamma-ray flashes. Recent improvements rose up the terrestrial gamma-ray flashes detection rate and lead to the observation, for the first time, of multiple events occurring within single thunderstorm processes.

In camera calibration the goal is to determine a set of camera parameters that describe the mapping between 3-D reference coordinates and 2-D image ones. Correction for image distortion in cameras is an important topic in order to obtain accurate information from the vision systems. A review of calibration techniques for the vision systems is presented among the different methods for camera calibration found in literature. The advantages and limitations of these techniques are also discussed. This work analyzes the techniques that can be useful in modern industrial contest with the aim of knowing the effective distortion of the lens and the possibility to determinate the measurement uncertainty of the vision system.

The Josephson effect is worldwide used as a basis for constant reference voltages in national metrological institutes and in calibration laboratories of industry. Research on Josephson voltage standards is aiming at a fundamental change also in the metrology of the volt for AC and arbitrary waveforms: programmable Josephson voltage standards converting a digital code into a quantum-accurate stepwise waveform are already available in primary laboratories and even more advanced standards for converting sub-nanosecond binary coded pulses into any arbitrary signal with quantum accuracy are now actively developed and tested. A new experimental setup based on a two-stage Gifford-McMahon cryocooler has been developed at INRiM for the operation of AC-Josephson voltage standards. Among its distinct features, the possibility of employing both the aforementioned techniques (programmable and pulsed Josephson voltage standards) is particularly interesting. Quantum-based AC voltage sine waves have been synthesized with both programmable and pulse-driven arrays, although their accuracy is still limited by thermal oscillations due to the cryocooler piston motion.

The accurate determination of gaseous pollutants is fundamental for the monitoring of the trends of these analytes in the environment and the application of the metrological concepts to this field is necessary to assure the reliability of the measurement results. In this work, an overview of the activity carried out at Istituto Nazionale di Ricerca Metrologica to establish the metrological traceability of the measurements of gaseous atmospheric pollutants, in particular of carbon dioxide (CO₂), is presented. Two primary methods, the gravimetry and the dynamic dilution, are used for the preparation of reference standards for composition which can be used to calibrate sensors and analytical instrumentation. At present, research is carried out to lower the measurement uncertainties of the primary gas mixtures and to extend their application to the oceanic field. The reason of such investigation is due to the evidence of the changes occurring in seawater carbonate chemistry, connected to the rising level of CO₂ in the atmosphere. The well established activity to assure the metrological traceability of CO₂ in the atmosphere will be applied to the determination of CO₂ in seawater, by developing suitable reference materials for calibration and control of the sensors during their routine use.

Two-photon entangled quantum states are a fundamental tool for quantum information and quantum cryptography. A complete description of a generic quantum state is provided by its density matrix: the technique allowing experimental reconstruction of the density matrix is called quantum state tomography. Entangled states density matrix reconstruction requires a large number of measurements on many identical copies of the quantum state. An alternative way of certifying the amount of entanglement in two-photon states is represented by the estimation of specific parameters, e.g., negativity and concurrence. If we have a priori partial knowledge of our state, it's possible to develop several estimators for these parameters that require lower amount of measurements with respect to full density matrix reconstruction. The aim of this work is to introduce and test different estimators for negativity and concurrence for a specific class of two-photon states.

The inflationary mechanism has become the paradigm of modern cosmology over the last thirty years. However, there are several aspects of inflationary physics that are still to be addressed, like the shape of the inflationary potential. Regarding this, the so-called α-attractor models show interesting properties. In this work, the reconstruction of the effective potential around the global minimum of these particular potentials is provided, assuming a detection of permille-order for the tensor-to-scalar-ratio by forthcoming cosmic microwave background or gravitational waves experiments.

The LIGO observation of GW150914 has inaugurated the gravitational-wave astronomy era and the possibility of testing gravity in extreme regimes. While distorted black holes are the most convincing sources of gravitational waves, similar signals might be produced also by other compact objects. In particular, we discuss what the gravitational-wave ringdown could tell us about the nature of the emitting object, and how measurements of the tidal Love numbers could help us in understanding the internal structure of compact dark objects.

We suggest the possibility that the discrepancy between general relativity and astronomical observations in the rotational speed of flat galactic disks may be seen as a potential first evidence of a quantum gravity macroscopic effect instead of the existence of still elusive dark matter. We try to give an entropic interpretation of gravity which leads to Modified Newtonian Dynamics and in the same spirit we suggest further explorations in the strong field regime.

A central problem in quantum field theory is the computation of scattering amplitudes. However, traditional methods are impractical to calculate high order phenomenologically relevant observables. Building on a few decades of astonishing progress in developing non-standard computational techniques, it has been recently conjectured that amplitudes in planar ${\mathcal{N}}=4$ super Yang-Mills are given by the volume of the (dual) amplituhedron. After providing an introduction to the subject at tree-level, we discuss a special class of differential equations obeyed by the corresponding volume forms. In particular, we show how they fix completely the amplituhedron volume for next-to-maximally helicity violating scattering amplitudes.

In the last decade, physical and geometrical investigations about the relationship between horizon thermodynamics and gravitational dynamics suggest that gravity could be an emergent phenomenon. Among the others, Padmanabhan's theory of "emergent gravity" focus on the concept of spacetime as an effective macroscopic description of a more fundamental microscopic theory ("atoms of spacetime") at the Planck scales, thus aiming to reconcile the large scale description of gravity and the small one of quantum physics. However, some mathematical aspects of this approach are still not clear as, for example, the derivation of Einstein equations from a suitable entropy functional (and not from an action as in standard General Relativity). Thus in this work, a direct and non-trivial link between Padmanabhan's entropy used in emergent gravity and standard General Relativity action is established. To do that, Augmented Variational Principles and Kerr-Schild metrics will be used. We shall also discuss how this link accounts for the details of the variation of Padmanabhan's action based on gravitational entropy. It will also clarify the role of the background metric used in Padmanabhan's functional and its non-dynamical role.