Bøger i Springer Theses serien

This thesis makes significant advances in the use of microspheres in optical traps as highly precise sensing platforms. While optically trapped microspheres have recently proven their dominance in aqueous and vacuum environments, achieving state-of-the-art measurements of miniscule forces and torques, their sensitivity to perturbations in air has remained relatively unexplored. This thesis shows that, by uniquely operating in air and measuring its thermally-fluctuating instantaneous velocity, an optically trapped microsphere is an ultra-sensitive probe of both mass and sound. The mass of the microsphere is determined with similar accuracy to competitive methods but in a fraction of the measurement time and all while maintaining thermal equilibrium, unlike alternative methods. As an acoustic transducer, the air-based microsphere is uniquely sensitive to the velocity of sound, as opposed to the pressure measured by a traditional microphone. By comparison to state-of-the-art commercially-available velocity and pressure sensors, including the world¿s smallest measurement microphone, the microsphere sensing modality is shown to be both accurate and to have superior sensitivity at high frequencies. Applications for such high-frequency acoustic sensing include dosage monitoring in proton therapy for cancer and event discrimination in bubble chamber searches for dark matter. In addition to reporting these scientific results, the thesis is pedagogically organized to present the relevant history, theory, and technology in a straightforward way.

This thesis presents significant advances in the use of neural networks to study the properties of neutrinos. Machine learning tools like neural networks (NN) can be used to identify the particle types or determine their energies in detectors such as those used in the NOvA neutrino experiment, which studies changes in a beam of neutrinos as it propagates approximately 800 km through the earth. NOvA relies heavily on simulations of the physics processes and the detector response; these simulations work well, but do not match the real experiment perfectly. Thus, neural networks trained on simulated datasets must include systematic uncertainties that account for possible imperfections in the simulation. This thesis presents the first application in HEP of adversarial domain generalization to a regression neural network. Applying domain generalization to problems with large systematic variations will reduce the impact of uncertainties while avoiding the risk of falsely constraining the phase space. Reducing the impact of systematic uncertainties makes NOvA analysis more robust, and improves the significance of experimental results.

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.

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 thesis explores the physics of non-equilibrium quantum dynamics in homogeneous two-dimensional (2D) quantum gases. Ultracold quantum gases driven out of equilibrium have been prominent platforms for studying quantum many-body physics. However, probing non-equilibrium dynamics in conventionally trapped, inhomogeneous atomic quantum gases has been a challenging task because coexisting mass transport and spreading of quantum correlations often complicate experimental analyses. In this work, the author solves this technical hurdle by producing ultracold cesium atoms in a quasi-2D optical box potential. The exquisite optical trap allows one to remove density inhomogeneity in a degenerate quantum gas and control its dimensionality. The author also details the development of a high-resolution, in situ imaging technique to monitor the evolution of collective excitations and quantum transport down to atomic shot-noise, and at the length scale of elementary collective excitations. Meanwhile, tunable Feshbach resonances in ultracold cesium atoms permit precise and dynamical control of interactions with high temporal and even spatial resolutions. By employing these state-of-the-art techniques, the author performed interaction quenches to control the generation and evolution of quasiparticles in quantum gases, presenting the first direct measurement of quantum entanglement between interaction quench generated quasiparticle pairs in an atomic superfluid. Quenching to attractive interactions, this work shows stimulated emission of quasiparticles, leading to amplified density waves and fragmentation, forming 2D matter-wave Townes solitons that were previously considered impossible to form in equilibrium due to their instability. This thesis unveils a set of scale-invariant and universal quench dynamics and provides unprecedented tools to explore quantum entanglement transport in a homogenous quantum gas.

This thesis proposes useful tools, on-the-fly trajectory mapping method and Reaction Space Projector (ReSPer), to analyze chemical reaction mechanisms by combining the reaction route map and the ab initio molecular dynamics. The key concept for the proposed tools is the Cartesian distance between pairwise molecular structures, and a practical procedure to get the optimal distance is introduced. The on-the-fly trajectory mapping method tracks the distance function between reference structures and molecular structures along the trajectory. Although this method provides fruitful insight into dynamic reaction behaviors, the visualization of reaction routes into a low-dimensional space is still challenging because of the multi-dimensionality. ReSPer successfully constructs a low-dimensional reaction space defined by mathematically-selected principal coordinates representing mutual distance relationships in the full-dimensional space. ReSPer also enables us to project trajectories into the reaction space in the reduced dimension. In this thesis, these methods are applied to several reactions, including bifurcating and photochemical reactions, revealing dynamically-allowed reaction mechanisms. This thesis provides robust and versatile tools to elucidate dynamical reaction routes on the basis of the reduced-dimensionality reaction route map and will help control chemical reaction dynamics and select descriptors for machine learning.

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.

The laws of nature encompass the small, the large, the few, and the many. In this book, we are concerned with classical (i.e., not quantum) many-body systems, which refers to any microscopic or macroscopic system that contains a large number of interacting entities. The nearest-neighbor Ising model, originally developed in 1920 by Wilhelm Lenz, forms a cornerstone in our theoretical understanding of collective effects in classical many-body systems and is to date a paradigm in statistical physics.Despite its elegant and simplistic description, exact analytical results in dimensions equal and larger than two are difficult to obtain. Therefore, much work has been done to construct methods that allow for approximate, yet accurate, analytical solutions. One of these methods is the Bethe-Guggenheim approximation, originally developed independently by Hans Bethe and Edward Guggenheim in 1935. This approximation goes beyond the well-known mean field approximation and explicitly accounts for pair correlations between the spins in the Ising model.In this book, we embark on a journey to exploit the full capacity of the Bethe-Guggenheim approximation, in non-uniform and non-equilibrium settings. Throughout we unveil the non-trivial and a priori non-intuitive effects of pair correlations in the classical nearest-neighbor Ising model, which are taken into account in the Bethe-Guggenheim approximation and neglected in the mean field approximation.

This book reports a study of a class of Dion-Jacobson-type layered perovskite oxides in which high oxide-ion conductivities in phases were discovered for the first time in the world. The oxide-ion conductors are important in various energy conversion devices and environmental protection applications such as solid-oxide fuel cells, oxygen gas sensors, oxygen separation membranes, and oxygen-based catalysts. The discoveries are based on a new screening method, called the bond valence method, combined with an original design concept. The present finding of high oxide-ion conductivity reported in the thesis suggested the potential of Dion-Jacobson phases as a platform to identify superior oxide-ion conductors.To understand what causes such high oxide-ion conductivities in these layered perovskite oxides, the author analyzed their crystal structures at high temperature and described the relationship between oxide-ion conductivities and their crystal structures. A deep understanding of the mechanisms of oxide-ion diffusivity at an atomic level in the Dion-Jacobson phases is clarified.The discovery of these materials, the new screening method, and the original design concept make possible the realization of many environment-friendly technologies. The findings in this thesis facilitate the possibilities for many novel applications that will help lead to a sustainable future.

The thesis tackles two distinct problems of great interest in gravitational mechanics ¿ one relativistic and one Newtonian. The relativistic one is concerned with the "first law of binary mechanics", a remarkably simple variational relation that plays a crucial role in the modern understanding of the gravitational two-body problem, thereby contributing to the effort to detect gravitational-wave signals from binary systems of black holes and neutron stars. The work reported in the thesis provides a mathematically elegant extension of previous results to compact objects that carry spin angular momentum and quadrupolar deformations, which more accurately represent astrophysical bodies than mere point particles. The Newtonian problem is concerned with the isochrone problem of celestial mechanics, namely the determination of the set of radial potentials whose bounded orbits have a radial period independent of the angular momentum. The thesis solves this problem completely in a geometrical way and explores its consequence on a variety of levels, in particular with a complete characterisation of isochrone orbits. The thesis is exceptional in the breadth of its scope and achievements. It is clearly and eloquently written, makes excellent use of images, provides careful explanations of the concepts and calculations, and it conveys the author¿s personality in a way that is rare in scientific writing, while never sacrificing academic rigor.

This book presents the observation and the control of spin-polarized electrons in Rashba thin films and topological insulators, including the first observations of a weak topological insulator (WTI) and a higher-order topological insulator (HOTI) in bismuth halides. It begins with a general review of electronic structures at the solid surface and mentions that an electron spin at a surface is polarized due to the Rashba effect or topological insulator states with strong spin-orbit coupling. Subsequently it describes the experimental techniques used to study these effects, that is, angle-resolved photoemission spectroscopy (ARPES). Further it moves its focus onto the experimental investigations, in which mainly two different systems-noble metal thin films with the Rashba effects and bismuth halides topological insulators-are used. The study of the first system discusses the role of wavefunctions in spin-splitting and demonstrates a scaling law for the Rashba effect in quantum well films for the first time. High-resolution spin-resolved ARPES plays a vital role in systematically trace the thickness-evolution of the effect. The study of the latter material is the first experimental demonstration of both a WTI and HOTI state in bismuth iodide and bismuth bromide, respectively. Importantly, nano-ARPES with high spatial resolution is used to confirm the topological surface states on the side surface of the crystal, which is the hallmark of WTIs.The description of the basic and recently-developed ARPES technique with spin-resolution or spatial-resolution, essential in investigating spin-polarized electrons at a crystal surface, makes the book a valuable source for researchers not only in surface physics or topological materials but also in spintronics and other condensed-matter physics.

How planets form is one of the long-standing questions in astrophysics. In particular, formation scenarios of planetesimals which are kilometer-sized bodies and a precursor of planets are still unclear and under debate although some promising mechanisms have been proposed.This book highlight disk instabilities that have the potential to explain the origin of planetesimals. Using linear analyses and numerical simulations, it addresses how a disk evolves through the development of instabilities, and also presents a new instability driven by dust coagulation. As a result, the simulation demonstrates a scenario of planetesimal formation: A successive development of multiple instabilities triggers planetesimal formation in resulting dusty rings.

This book constructs a non-Bloch band theory and studies physics described by non-Hermitian Hamiltonian in terms of the theory proposed here.In non-Hermitian crystals, the author introduces the non-Bloch band theory which produces an energy spectrum in the limit of a large system size. The energy spectrum is then calculated from a generalized Brillouin zone for a complex Bloch wave number. While a generalized Brillouin zone becomes a unit circle on a complex plane in Hermitian systems, it becomes a circle with cusps in non-Hermitian systems. Such unique features of the generalized Brillouin zone realize remarkable phenomena peculiar in non-Hermitian systems. Further the author reveals rich aspects of non-Hermitian physics in terms of the non-Bloch band theory. First, a topological invariant defined by a generalized Brillouin zone implies the appearance of topological edge states. Second, a topological semimetal phase with exceptional points appears, The topological semimetal phase is unique to non-Hermitian systems because it is caused by the deformation of the generalized Brillouin zone by changes of system parameters. Third, the author reveals a certain relationship between the non-Bloch waves and non-Hermitian topology.

This book highlights the most complete characterization of the Higgs boson properties performed to date in the "golden channel," i.e., decay into a pair of Z bosons which subsequently decay into four leptons. The data collected by the CMS experiment in the so-called Run-II data-taking period of the LHC are used to produce an extensive set of results that test in detail the predictions of the Standard Model.Given the remarkable predictive power of the SM when including the Higgs boson, possible new physics will require even more extensive studies at higher statistics. A massive upgrade of the detectors is necessary to maintain the current physics performance in the harsh environment of the High-Luminosity LHC (HL-LHC) project, expected to start by the end of 2027. The CMS Collaboration will replace the current endcap calorimeters with a High Granularity Calorimeter (HGCAL). The HGCAL will be the very first large-scale silicon-based imaging calorimeter ever employed in a high-energy physics experiment. This book presents the results of the analysis of the test beam data collected with the first large-scale prototype of the HGCAL. The results of this analysis are used to corroborate the final design of the HGCAL and its nominal physics performance expected for the HL-LHC operations.

This book offers a systematic study of control algorithms applied in the operation of solar membrane distillation (SMD) facilities. After a short introduction to membrane distillation systems powered by solar energy, it reports on the various stages of the development of a comprehensive operating strategy, based on modelling, control, and optimization techniques, which enables an improved operation of SMD plants helping the commercialization of the SMD technology. A special focus of the research was to maximize the distillate production of the MD modules while reducing their thermal energy consumption, being those two important weaknesses of the current technology, as well as their minimizing operating costs. The optimised operating strategies were tested in a real pilot plant located at Plataforma Solar de Almería (a dependency of the Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, of Spain). All in all, this thesis offers extensive information on control and modeling algorithms, and on their practical applications in solar membrane distillation plants.

This thesis presents research on novel laboratory-scale synchrotron X-ray sources based on inverse Compton scattering and applications of their X-ray radiation using the Munich Compact Light Source (MuCLS) as an example. It provides an introduction to the theory of this laser-electron interaction, laser resonators and X-ray interactions with matter. On this basis, upgrades to the laser system including the development of a new laser optic, X-ray beam stabilisation and two techniques for fast X-ray energy switching of inverse Compton sources are presented. On the application side, the beamline, designed and developed for the inverse Compton X-ray source at the MuCLS, is described before various techniques and applications are demonstrated at this laboratory-scale synchrotron X-ray facility. Among them are K-edge subtraction imaging, X-ray phase contrast imaging and X-ray absorption spectroscopy. Additionally, a new X-ray microscopy technique, called full-field structured-illumination super-resolution X-ray transmission microscopy, is presented.Apart from research conducted at the MuCLS, this thesis contains an in-depth overview on the state of the art of the various types of inverse Compton X-ray sources that have been realised so far. Accordingly, this thesis may serve as a guide and reference work for researchers working with inverse Compton X-ray sources as well as future users of such devices.

This book reports on a comprehensive study on a novel high-power converter, i.e. a Modular Multilevel Converter with Interleaved Half-bridge Submodules (ISM-MMC). It describes in depth its average model, the operating principles, as well as a new control method and a hybrid modulation strategy that help to exploit the benefits of the interleaving scheme. The new power converter is particularly advantageous for high-current applications that require superb quality of input/output waveforms. Moreover, this book reports on a systematic study of the current balancing problem between parallel-connected units that commutate in non-simultaneous fashion. This is a typical issue in interleaved converters, however here it is analyzed for the first time in relation to MMC-based structures. Two control strategies are proposed to cope with this matter. By using a sensorless regulation scheme, the number of required current transducers has been minimized, reducing complexity, cost, and footprint of the hardware, while providing converter with a fast and accurate current balancing. This book also offers a comprehensive comparison between several practical designs of ISM-MMC and classical MMC for an ultra-fast electrical vehicle charger. All in all, it provides graduate students and researchers, as well as field engineers and professionals with extensive information and essential practical details on the state-of-the-art MMC and ISM-MMC design.

This book introduces readers to the preparation of metal nanocrystals and its applications. In this book, an important point highlighted is how to design noble metal nanocrystals at the atomic scale for energy conversion and storage. It also focuses on the controllable synthesis of water splitting electrode materials including anodic oxygen evolution reaction (OER) and cathode hydrogen evolution reaction (HER) at the atomic level by defect engineering and synergistic effect. In addition, in-situ technologies and theoretical calculations are utilized to reveal the catalytic mechanisms of catalysts under realistic operating condition. The findings presented not only enrich research in the nano-field, but also support the promotion of national and international cooperation.

This book presents an analytical framework for calculating the fracture toughness of generally layered beam structures with an elastically coupled response and hygrothermal stresses. The beam under study features several peculiarities: it consists of multiple layers of dissimilar materials, features bending-extension coupling, and contains residual hygrothermal stresses. Here, a generic analytical model is proposed to compute the energy release rate and the mode mixity. Mechanics of composite materials, crack closure integral, and energetic methods are among the theoretical tools employed for developing the model.A wealth of new closed-form expressions is presented, together with their validation through finite element analyses, which enables investigating various material systems and testing configurations. Experimentalists will find directions for the design and interpretation of delamination tests on laminated composites with uncommon stacking sequences. At the same time, theoreticians can exploit the analytical solution as a benchmark test for more refined analytical and numerical models. Furthermore, the book gives novel insights into the fracture behavior of a titanium-to-CFRP adhesive joint, which is intended for application in the hybrid laminar flow control of a future aircraft. It reports on experiments and theoretical analyses that help understand the behavior of this novel joint. All in all, this book offers extensive updates on methods for fracture analysis of materials with an elastically coupled behavior and residual stresses. It addresses students, researchers, and engineers alike.

This book focuses on the development of novel functionalized organoboron compounds and those synthetic methods. High degrees of chemo-, regio-, and stereoselectivities of the borylation reactions are attained through catalyst design and optimization. Furthermore, the selectivity-determining mechanisms are analyzed with state-of-the-art DFT and other computational methods.In this book, the author synthesizes some multi-substituted alkenyl and allylic boronates via borylation reactions using a copper(I)/diboron catalyst system. Those compounds contain novel densely substituted and distorted structures, which have not been accessed by other methods. The high stereoselectivities are achieved by the optimization of the catalyst, especially the ligand. Some new ligands are also developed in this book. Furthermore, the derivatization of the borylation products is demonstrated to access the sterically demanding complex molecules. Also, the author performs computational analysis to reveal how the catalyst controls the selectivities. The deep insight into the reaction mechanism provides guides for rational catalyst design for not only copper(I) catalysis but also other transition metal catalysis. Thus, the content should be of interest to academic and industrial scientists in a wide range of areas.