Bøker i Springer Theses-serien

This book focuses on proposing a tsunami early warning system using data assimilation of offshore data. First, Green's Function-based Tsunami Data Assimilation (GFTDA) is proposed to reduce the computation time for assimilation. It can forecast the waveform at Points of Interest (PoIs) by superposing Green's functions between observational stations and PoIs. GFTDA achieves an equivalently high accuracy of tsunami forecasting to the previous approaches, while saving sufficient time to achieve an early warning. Second, a modified tsunami data assimilation method is explored for regions with a sparse observation network. The method uses interpolated waveforms at virtual stations to construct the complete wavefront for tsunami propagation. Its application to the 2009 Dusky Sound, New Zealand earthquake, and the 2015 Illapel earthquake revealed that adopting virtual stations greatly improved the tsunami forecasting accuracy for regions without a dense observation network. Finally, a real-time tsunami detection algorithm using Ensemble Empirical Mode Decomposition (EEMD) is presented. The tsunami signals of the offshore bottom pressure gauge can be automatically separated from the tidal components, seismic waves, and background noise. The algorithm could detect tsunami arrival with a short detection delay and accurately characterize the tsunami amplitude. Furthermore, the tsunami data assimilation approach is combined with the real-time tsunami detection algorithm, which is applied to the tsunami of the 2016 Fukushima earthquake. The proposed tsunami data assimilation approach can be put into practice with the help of the real-time tsunami detection algorithm.

This thesis investigates the detection efficiency of field-resolved measurements of ultrashort mid-infrared waves via electro-optic sampling for the first time. Employing high-power gate pulses and phase-matched upconversion in thick nonlinear crystals, unprecedented efficiencies are achieved for octave-spanning fields in this wavelength range. In combination with state-of-the art, high-power, ultrashort mid-infrared sources, this allows to demonstrate a new regime of linear detection dynamic range for field strengths from mV/cm to MV/cm-levels. These results crucially contribute to the development of field-resolved spectrometers for early disease detection, as fundamental vibrational modes of (bio-)molecules lie in the investigated spectral range.The results are discussed and compared with previous sensitivity records for electric-field measurements and reference is made to related implementations of the described characterization technique. Including a detailed theoretical description and simulation results, the work elucidates crucial scaling laws, characteristics and limitations. The thesis will thus serve as an educational introduction to the topic of field-resolved measurements using electro-optic sampling, giving detailed instructions on simulations and experimental implementations. At the same time, it showcases the state-of-the-art in terms of detection sensitivity for characterizing mid-infrared waves.

This book reports the establishment of a single-atomic layer metal of In and a novel (In, Mg) ultrathin film on Si(111) surfaces. A double-layer phase of In called "e;rect"e; has been extensively investigated as a two-dimensional metal. Another crystalline phase called "e;hex"e; was also suggested, but it had not been established due to difficulty in preparing the sample. The author succeeded in growing the large and high-quality sample of the hex phase and revealed that it is a single-layer metal. The author also established a new triple-atomic layer (In, Mg) film with a nearly freestanding character by Mg deposition onto the In double layer. This work proposes a novel method to decouple ultrathin metal films from Si dangling bonds.The present study demonstrates interesting properties of indium itself, which is a p-block metal both with metallicity and covalency. In this book, readers also see principles of various surface analysis techniques and learn how to use them and analyze the results in the real systems. This book is useful to researchers and students interested in surface science, particularly ultrathin metal films on semiconductor surfaces.

This book presents novel contributions in the development of solid-state-transformer (SST) technology both for medium-voltage (MV) and low-voltage (LV) utility grid interfaces, which can potentially augment the grid modernization process in the evolving power system paradigm. For the MV interface, a single-stage AC-DC SST submodule topology has been proposed, and its modulation and soft-switching possibilities are analysed, experimentally validated and adequately benchmarked. A control scheme with power balance capability among submodules is developed for MV grid-connected single-stage AC-DC SST for smooth operation under inevitable parameter drift scenario, and experimental validation shows excellent performance under drastic load change conditions. A novel machine learning-aided multi-objective design optimization framework for grid-connected SST is developed and experimentally validated, which equips a power electronics design engineer with meagre computational resources to find out the most optimal SST design in a convenient time-frame. This book has also contributed towards the development of dual-active-bridge (DAB)-type and non-DAB-type LV grid-interfaced isolated AC-DC converters by providing solutions to specific topology and modulation-related shortcomings in these two types of topologies. A comprehensive comparison of the DAB and non-DAB-type LVAC-LVDC converters reveals the superiority of DAB-type conversion strategy.

This book addresses the comprehensive understanding of Ni-rich layered oxide of lithium-ion batteries cathodes materials, especially focusing on the effect of dopant on the intrinsic and extrinsic effect to its host materials. This book can be divided into three parts, that is, 1. overall understanding of layered oxide system, 2. intrinsic effect of dopant on layered oxides, and 3. extrinsic effect of dopant on layered oxides. To truly understand and discover the fundamental solution (e.g. doping) to improve the Ni-rich layered oxides cathodic performance, understanding the foundation of layered oxide degradation mechanism is the key, thus, the first chapter focuses on discovering the true degradation mechanisms of layered oxides systems. Then, the second and third chapter deals with the effect of dopant on alleviating the fundamental degradation mechanism of Ni-rich layered oxides, which we believe is the first insight ever been provided. The content described in this book will provide research insight to develop high-performance Ni-rich layered oxide cathode materials and serve as a guide for those who study energy storage systems.

The thesis presents a systematic study of the Mpemba effect in a colloidal system with a micron-sized particle diffusing in a water bath. While the Mpemba effect, where a system's thermal relaxation time is a non-monotonic function of the initial temperature, has been observed in water since Aristotle's era, the underlying mechanism of the effect is still unknown. Recent studies indicate that the effect is not limited to water and has been studied both experimentally and numerically in a wide variety of systems. By carefully designing a double-well potential using feedback-based optical tweezers, the author demonstrates that an initially hot system can sometimes cool faster than an initially warm system. The author also presents the first observation in any system of another counterintuitive effect-the inverse Mpemba effect-where the colder of the two samples reaches the thermal equilibrium at a hot temperature first. The results for both the observations agree with theoretical predictions based on the Fokker-Planck equation. The experiments reveal that, for carefully chosen conditions, a strong version of both of the effects are observed where a system can relax to the bath temperature exponentially faster than under typical conditions.

This thesis presents the first realization of non-reciprocal energy transfer between two cantilevers by quantum vacuum fluctuations. According to quantum mechanics, vacuum is not empty but full of fluctuations due to zero-point energy. Such quantum vacuum fluctuations can lead to an attractive force between two neutral plates in vacuum ¿ the so-called Casimir effect ¿ which has attracted great attention as macroscopic evidence of quantum electromagnetic fluctuations, and can dominate the interaction between neutral surfaces at small separations. The first experimental demonstration of diode-like energy transport in vacuum reported in this thesis is a breakthrough in Casimir-based devices. It represents an efficient and robust way of regulating phonon transport along one preferable direction in vacuum. In addition, the three-body Casimir effects investigated in this thesis were used to realize a transistor-like three-terminal device with quantum vacuum fluctuations. These two breakthroughs pave the way for exploring and developing advanced Casimir-based devices with potential applications in quantum information science. This thesis also includes a study of the non-contact Casimir friction, which will enrich the understanding of quantum vacuum fluctuations.

Line intensity mapping (LIM) is an observational technique that probes the large-scale structure of the Universe by collecting light from a wide field of the sky. This book demonstrates a novel analysis method for LIM using machine learning (ML) technologies. The author develops a conditional generative adversarial network that separates designated emission signals from sources at different epochs. It thus provides, for the first time, an efficient way to extract signals from LIM data with foreground noise. The method is complementary to conventional statistical methods such as cross-correlation analysis. When applied to three-dimensional LIM data with wavelength information, high reproducibility is achieved under realistic conditions. The book further investigates how the trained machine extracts the signals, and discusses the limitation of the ML methods. Lastly an application of the LIM data to a study of cosmic reionization is presented. This book benefits students and researchers who are interested in using machine learning to multi-dimensional data not only in astronomy but also in general applications.

This book focuses on the development of high-performance carbon electrodes for sodium ion batteries (SIBs). By proposing folded-graphene as the high-density cathode with excellent rate capability, it provides insight into the interplay between oxygen functional groups and folded texture. It also highlights the superiority of ether electrolytes matching with carbon anodes, which are shown to deliver largely improved electrochemical performance. The achievements presented offer a valuable contribution to the carbon-based electrodes in SIBs.

This thesis describes in-depth studies of the remarkable electronic transport within the ultrahigh conductivity delafossite metals PtCoO_2 and PdCoO_2 using the tool of focused ion beam (FIB) microstucturing. Despite being first synthesised over 50 years ago, important questions remain regarding both the origin of the unusually high conductivity of these compounds and the consequences of their unique properties for unconventional electronic transport, such as that within the ballistic regime. The thesis explores both these areas.High-energy electron irradiation is used to examine the effects of deliberately introducing point defects into PdCoO_2 and PtCoO_2, demonstrating that the extremely low resistivity of these materials stems from an extreme purity as high as 1 defect in 120,000 atoms, rather than a novel scattering suppression mechanism. In addition, studies of the electronic transport in micron-scale squares of these metals show that their broadly hexagonal Fermi surfaces lead not only to long range ballistic behaviour but novel ballistic regime phenomena which cannot be observed in materials with a higher-symmetry Fermi surface.

This book elucidates fascinating electronic phenomena of unusual Bi2-square net in layered R2O2Bi (R: rare earth) compounds using two approaches: the fabrication of epitaxial thin films and the synthesis of bulk polycrystalline powders. The Bi2-square net compounds are a promising platform to explore exotic physical properties originating from the interplay between a two-dimensional electronic state and strong spin¿orbit coupling; however, there are few reports on Bi2-square net compounds due to the instability of unusual electronic configurations. The book presents the development of synthetic routes for R2O2Bi compounds, such as novel solid phase epitaxy techniques and chemical control of crystal structure, demonstrating the intrinsic physical properties of Bi2-square net for the first time. The most notable finding is the successful induction of two-dimensional superconductivity in Bi2-square net with the coexistence of rich electronic phases. The book also discusses the superconducting mechanisms and the effect of R cation substitution in detail and describes the mechanical properties of Bi2-square net. These findings overturn the results of previous studies of R2O2Bi. The book sheds light on hidden layered compounds, representing a significant advance in the field.

This Ph.D. book develops nanowire-assisted electroporation disinfection technology based on the flow-through porous electrode. The author presents pioneering results on theoretical modeling, experimental realization, and selected applications, showing the novel disinfection mechanism of electroporation guarantees an exceedingly low level of energy consumption. In this regard, three classes of novel dynamic behavior are investigated: (i) The developed nanowire-assisted flow-through electroporation disinfection technology enables great microbial disinfection performance with extremely low voltage (1V), which significantly reduce the formation potential of harmful disinfection by-products during the treatment process. (ii) The nanowire-assisted flow-through electroporation disinfection technology ensures no reactivation/regrowth of inactivated bacteria and meanwhile promotes the gradual death of damaged bacteria during the storage process. (iii) The application of high-frequency AC power supply (106 Hz) ensures the high microbial disinfection efficiency while suppressing the occurrence of electrochemical reactions and extending the electrode lifetime effectively.

This work systematically investigates the use of high-quality (high-Q) resonators as coding particles of chipless cooperative radar targets to overcome clutter. Due to their high-Q, the backscattered signature can outlast clutter and permit reliable readouts in dynamic environments as well as its integration in other types of cooperative radar targets for joint identification, sensing, and ranging capabilities.This is first demonstrated with temperature and pressure sensors in the microwave frequency range, which include the characterization of a novel temperature sensor for machine tool monitoring up to 400 (deg)C, as well as inside the machine. Afterwards, the thesis proposes and demonstrates the use of metallic as well as dielectric Electromagnetic BandGap (EBG) structures to enable the realization and to enhance the capabilities at mm-Wave and THz frequencies compared to microwave frequencies with compact monolithic multi-resonator cooperative radar targets. Furthermore, this work studies the integration of resonators as coding particles inside larger retroreflective configurations such as Luneburg lenses to achieve long-range and high accuracy for localization and, at the same time, frequency coding robust against clutter for identification. Finally, the successful readout of these cooperative radar targets is demonstrated in cluttered dynamic environments, as well as with readers based on Frequency-Modulated Continuous-Wave (FMCW) radars.

This thesis addresses the design of crystal structures using hydrogen bonds. In particular, it focuses on the design of functionalities and the control over the packing of molecular assemblies, based on molecular designs.Firstly, the synthesis and evaluation of a proton¿electron mixed conducting charge transfer salt is reported. Focusing on the difference in the strength of hydrogen bonds and weaker intermolecular interactions, a system was rationally designed and constructed where electron-conducting molecular wires were encapsulated within a proton-conducting matrix. Next, the investigation of structural phase transitions in a cocrystal consisting of hydrogen-bonded two-dimensional molecular assemblies is reported. Drastic rearrangements of hydrogen-bonded molecular assemblies in the cocrystal led to single-crystal-to-single-crystal phase transitions, resulting in anisotropic changes in the crystal shape. Furthermore, chemical modification of a component molecule in the cocrystal is reported. The modification afforded control over the stacking patterns of the two-dimensional molecular assemblies, i.e., sheets, and the mechanism was discussed considering the intersheet intermolecular interactions and molecular motion.It is suggested that hydrogen bonds are beneficial to construct molecular assemblies in molecular crystals because of their strength and well-defined directionality, and the consideration of coexisting weaker intermolecular interactions can lead to the design of whole crystal structures and, hence, functionalities. This thesis benefits students and researchers working on solid-state chemistry by presenting various methods for characterizing and evaluating the properties of molecular solids.

This book presents innovative laser desorption ionization (LDI)-active nanophotonic structures for addressing the challenges that matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is currently facing and for enhancing LDI efficiency. It presents a variety of cutting-edge nanophotonic structures to satisfy the mass-analytical needs of sensitivity, reproducibility, and quantification. As opposed to the commercialized, conventional organic matrix used in MALDI-MS, these nanostructures are validated to be highly effective in detecting small metabolites and drugs, highlighting their considerable potential in the mass spectrometry field. It also systematically elucidates fundamental LDI processes in terms of the photo-thermal, electronic, and structural characteristics of nanophotonic structures, offering mechanistic knowledge of LDI-MS. Even though LDI-MS performance is heavily influenced by a number of nanostructure parameters, relatively little is known about the LDI processes associated with those characteristics. An in-depth understanding of nanostructure characteristics and LDI mechanisms thus paves the way for more effective, rational design and development of nanostructures with improved LDI capabilities. Further, with a focus on multiple cascades in nanostructure functions in response to laser pulse stimuli, this book provides detailed, step-by-step procedures to design and construct a nanophotonic, LDI-active platform, which may serve as a roadmap for graduate students in the field of mass spectrometry. Readers, including graduate students, researchers, and experts working in the related areas of mass spectrometry, nanophotonics, and material science and material engineering, will find a wealth of useful information in this book.

This book introduces readers to the preparation of two-dimensional metal sulfide/oxide for CO2 photoreduction. Based on two-dimensional metal sulfide/oxide materials, this book establishes the structure-to-property relationships of photocatalyst for CO2 photoreduction, and reveals the intrinsic mechanism of the CO2 photoreduction by virtue of the in situ characterization techniques and the density functional theory calculations. It is anticipated that this book will help to identify empirical guidelines for designing and fabricating high-performance catalysts of solar-driven CO2 reduction.

This thesis makes significant advances towards an understanding of superconductivity in the cuprate family of unconventional, high-temperature superconductors. Even though the high-temperature superconductors were discovered over 35 years ago, there is not yet a general consensus on an acceptable theory of superconductivity in these materials. One of the early proposals suggested that collective magnetic excitations of the conduction electrons could lead them to form pairs, which in turn condense to form the superconducting state at a critical temperature Tc. Quantitative calculations of Tc using experimental data were, however, not available to verify the applicability of this magnetic mechanism. In this thesis, the author constructed an angle-resolved photoemission apparatus that could provide sufficiently accurate data of the electronic excitation spectra of samples in the normal state, data which was furthermore unusually devoid of any surface contamination. The author also applied the Bethe-Salpeter method to his uncommonly pristine and precise normal state data, and was able to predict the approximate superconducting transition temperatures of different samples. This rare combination of experiment with sophisticated theoretical calculations leads to the conclusion that antiferromagnetic correlations are a viable candidate for the pairing interaction in the cuprate superconductors.

This book introduces novel purification technology for the complex oligonucleotide libraries. Since the concept of synthesizing oligonucleotides (oligos) has been proposed, research fields such as nucleic acid-based therapies (CRISPR-Cas9, DNA/RNA vaccines, RNAi), synthetic biology, protein engineering, and DNA-based data storage have bloomed. The COVID-19 pandemic underscores the potential of nucleic acid-based technologies, such as vaccines or diagnostics. As they emerge as the most promising weapons against the current pandemic, increasing need for highly accessible nucleic acid purification technologies is expected. To meet this demand, an oligo purification technology that can be applied to complex oligo libraries and can purify oligos with single-base resolution is developed. In addition, the purification technology can be applied to highly complex oligo libraries of different lengths, enabling the simultaneous purification of complex oligo libraries with different lengths. The proposed technology can be easily accessed by users and would help accelerate numerous research fields that utilize oligos as fundamental building blocks.

In this thesis, attention was paid to several novel oxygenated fuels¿carbonates, polyethers and ketones. Combustion kinetic investigations were performed for typical representative compounds, including dimethyl carbonate, diethyl carbonate, cyclopentanone, 3-pentanone, 1,2-dimethoxyethane and dimethoxymethane. For experiments, suitable diagnostic techniques were used to measure the detailed speciation information of the target fuels under different conditions. For kinetic modeling, rate coefficients for crucial elementary reactions were obtained through high-level theoretical calculations. Based on that, validated kinetic models with good predictive performances were developed. On the basis of experimental measurements and model interpretations, this work highlighted two important combustion characteristics regarding the practical use: the pollutant formation and the ignition performance. Besides, the correlation between oxygen-containing functional groups and the aforementioned combustion characteristics was revealed. To reveal the potential interactions between the reaction networks of oxygenated additives and the hydrocarbon base fuels during combustion. Chemical structures of laminar premixed flames fueled by binary fuels were measured, and by changing the initial fuel compositions, the addition effects of the oxygenates on the fuel consumption and pollutant formation behaviors were explored. It was found that complicated chemical interactions do not exist in the reaction networks under the investigated conditions.

This thesis highlights research explorations in quantum contextuality with photons.Quantum contextuality is one of the most intriguing and peculiar predictions of quantum mechanics. It is also a cornerstone in modern quantum information science. It is the origin of the famous quantum nonlocality and various nonclassical paradoxes. It is also a resource for many quantum information processing tasks and even universal quantum computing. Therefore, the study of quantum contextuality not only advances the comprehension of the foundations of quantum physics, but also facilitates the practical applications of quantum information technology.In the last fifteen years, the study of quantum contextuality has developed from a purely theoretical level to a stage where direct experimental tests become amenable. However, the experimental research on contextuality at the current stage largely focuses on direct validations of some most famous predictions of contextuality, while other forms of contextuality and its practical applications in quantum information science are rarely involved. The research in this thesis is committed to bridge this gap from two directions: (1) to construct and test stronger forms of contextuality and relieve the requirements of contextuality experiments on experimental platforms, and (2) to explore the connections between contextuality and the other concepts in quantum information science and directly demonstrate the application of contextuality in broader scenarios. Specifically, the thesis have discussed the research topics about the relationship between quantum contextuality and nonlocality, the ¿all-versus-nothing¿ paradoxes from quantum contextuality, the ore- and post-selection paradoxes from quantum contextuality, and the topological protection and braiding dynamics of quantum contextuality in quasiparticle systems.

This thesis describes the development of iron-catalyzed thienyl C¿H/C¿H coupling. This is applied to the synthesis of highly conjugated and electron-rich thiophene compounds of interest in materials science by utilization of low redox potential of iron in combination with a mild oxalate oxidant.Transition-metal-catalyzed C(sp2)¿H/C(sp2)¿H coupling has attracted much attention as one of the most straightforward methods to construct C(sp2)¿C(sp2) bonds. However, application of this ideal transformation to the synthesis of redox-sensitive pi-materials was hindered by the requirement of a strong oxidant for catalyst turnover. This limitation originates primarily from the large redox potential of conventional transition-metal catalysts such as palladium and rhodium. This thesis shows that the efficiency of C¿H activation was significantly improved by introduction of a new conjugated tridentate phosphine ligand, giving direct access to polymeric thiophene materials from simple thiophene monomers. Considering the importance of environmentally friendly organic synthesis in terms of UN Sustainable Development Goals, the reactions described herein highlight the potential of iron, the most abundant transition-metal on earth, for the direct synthesis of functional small molecules and polymers of importance in energy device applications.

This book highlights the doctoral research of the author on electronic band structure engineering and ultrafast dynamics of Dirac semimetals. Dirac semimetals exhibit unique electronic band structure and novel physical properties with rich light-matter interaction, which inspires a wide range of potential applications. Enabling band engineering and revealing ultrafast dynamics of Dirac semimetals is therefore important. In the research work covered by the book, the first ultrafast time- and angle-resolved photoemission spectroscopy with tunable probe photon energy is developed, providing new opportunities for exploring ultrafast dynamics in 3D quantum materials. Using the spectroscopy, the author investigates the band structure engineering and ultrafast dynamics of Dirac semimetals, realizing the long-sought-after chiral symmetry breaking in a Kekulé-ordered graphene with flat band and revealing the ultrafast dynamics of Dirac fermions in 3D Dirac semimetal for the first time. The work advances the research of the electronic structure of Dirac semimetals in two aspects. Firstly, it identifies the Kekulé-ordered graphene as a new system for exploring chiral symmetry breaking- related physics and flat band- induced instability, providing a very rare system to investigate their interplay. Secondly, it solves the long-standing challenge of directly visualizing the non-equilibrium electronic structure of 3D Dirac semimetal and opens up new opportunities for exploring the light-matter interaction in 3D quantum materials, especially the light-induced topological phase transitions in 3D topological materials.

The task of signal detection is deciding whether signals of interest exist by using their observed data. Furthermore, signals are reconstructed or their key parameters are estimated from the observations in the task of signal recovery. Sparsity is a natural characteristic of most of signals in practice. The fact that multiple sparse signals share the common locations of dominant coefficients is called by joint sparsity. In the context of signal processing, joint sparsity model results in higher performance of signal detection and recovery. This book focuses on the task of detecting and reconstructing signals with joint sparsity. The main contents include key methods for detection of joint sparse signals and their corresponding theoretical performance analysis, and methods for joint sparse signal recovery and their application in the context of radar imaging.

This book explores the Higgs boson and its interactions with fermions, as well as the detector technologies used to measure it. The Standard Model of Particle Physics has been a groundbreaking theory in our understanding of the fundamental properties of the universe, but it is incomplete, and there are significant hints which require new physics. The discovery of the Higgs boson in 2012 was a substantial confirmation of the Standard Model, but many of its decay modes remain elusive. This book presents the latest search for Higgs boson decays into c-quarks using a proton-proton collision dataset collected by the ATLAS experiment at the Large Hadron Collider (LHC). This decay mode has yet to be observed and requires advanced machine learning algorithms to identify c-quarks in the experiment. The results provide an upper limit on the rate of Higgs boson decays to c-quarks and a direct measurement of the Higgs boson coupling strength to c-quarks. The book also discusses the future of particle physics and the need for significant improvements to the detector to cope with increased radiation damage and higher data rates at the High-Luminosity LHC. It presents the characterization of the ATLAS pixel detector readout chip for the inner detector upgrade (ITk). The chip was subjected to irradiations using X-rays and protons to simulate the radiation environment at the HL-LHC. The tests showed that all readout chip components, including the digital logic and analogue front-end, are sufficiently radiation-tolerant to withstand the expected radiation dose. Finally, this book describes monolithic pixel detectors as a possible technology for future pixel detectors. This book is ideal for individuals interested in exploring particle physics, the Higgs boson, and the development of silicon pixel detectors.

The absence of new physics at the TeV scale observed thus far at the Large Hadron Collider (LHC) motivates an increasing focus on searches for weakly-coupled new particles and exotic signatures. In particular, particles with macroscopic mean proper lifetimes, known as long-lived particles (LLPs), are of significant interest due to their ability to elude the majority of searches which rely on the assumption that Beyond Standard Model particles decay close to the primary interaction point. Many models which aim to solve various issues with the Standard Model (SM) introduce new particles with lifetimes that are either unconstrained, or even shown to prefer the macroscopic regime. These theories often point to the Higgs boson as a possible portal to new physics, with exotic Higgs decays being the primary phenomenological consequence and means of discovery. It is well motivated both from theory and experimental constraints to consider the scenario in which the particles produced in these exotic decays have macroscopic proper lifetimes and give rise to unique detector signatures.This work describes a search for exotic decays of the Higgs boson to two long-lived, neutral, spin-0 particles which subsequently decay to pairs of b quarks, giving the striking signature of displaced hadronic jets in the ATLAS inner detector. Several other ATLAS searches have probed this decay topology previously, excluding branching ratios of the Higgs boson to LLPs of more than 10% for proper lifetimes greater than 100mm. These searches relied on dedicated triggers designed to select events with LLPs decaying in the ATLAS calorimeter or muon spectrometer. The lack of an equivalent trigger for LLP decays in the ATLAS inner detector has been a limiting factor in probing LLP lifetimes less than 100mm. To circumvent the difficulty of triggering on LLP decays, the search presented in this thesis exploits the ZH associated production mode, relying on leptonic trigger signatures to select interesting events. This is the first search for Higgs boson decays into LLPs to exploit this analysis methodology and additionally makes use of several novel methods for both background rejection and background estimation.No excess over Standard Model predictions is observed, and upper limits are set on the branching ratio of the Higgs boson to LLPs . Depending on the mass of the LLP, branching ratios greater than 10% are excluded for lifetimes as small as 4mm and as large as 100mm, probing an important gap in the ATLAS exotic Higgs decay programme. In comparison to the previous searches for Higgs decays to LLPs, these are among the most stringent limits placed on this scenario, and for LLPs with masses below 40 GeV these results represent the strongest existing constraints on the branching ratio of the Higgs boson to LLPs in this lifetime regime.

The structure of quantum theory permits interference of indistinguishable paths. At the same time, however, it also limits such interference to certain orders and any higher-order interference is prohibited. This thesis develops and studies concepts to test quantum theory with higher-order interference using many-particle correlations, the latter being generally richer and typically more subtle than single-particle correlations. It is demonstrated that quantum theory in general allows for interference up to order 2M in M-particle correlations. Depending on the mutual coherence of the particles, however, the related interference hierarchy can terminate earlier. In this thesis, we show that mutually coherent particles can exhibit interference of the highest orders allowed. We further demonstrate that interference of mutually incoherent particles truncates already at order M+1, although interference of the latter is principally more multifaceted than their coherent counterpart. We introduce two families of many-particle Sorkin parameters, whose members are expected to be all zero when quantum mechanics holds. As proof of concept, we demonstrate the disparate vanishing of such higher-order interference terms as a function of coherence in experiments with mutually coherent and incoherent sources. Finally, we investigate the influence of exotic kinked or looped quantum paths, which are permitted by Feynman's path integral approach, in such setups.

This book offers a comprehensive study concerning the reliability of renewable electricity production in the Faroe Islands. The first part reports on a RoadMap with investments in generation, storage and transmission capacity. Multiple scenarios, considering different technologies, are analysed. Practical constraints like the local resource potential, power plant locations and sizes are discussed, as well as the potential of tidal power. The second part of the book describes dynamic simulations studies carried out to investigate grid stability of the power system on the isolated island of Suðuroy. The available information about governor and automatic voltage regulators of the synchronous generators was very limited, therefore different approaches were combined to parameterise and validate the dynamic models. All in all, this book offers extensive information concerning the transition of the Faroese power system into a 100% renewable system. It ispractice-oriented, and describes methods that can be applied to other power systems as well.