Bücher der Reihe Springer Theses

This thesis describes two groundbreaking measurements in the precision frontier at the LHC: the first ever differential measurement of the Z-associated single top quark (tZq) production, and the luminosity measurement using Z boson production rate for the first time in CMS. Observed only in 2018, the tZq process is of great importance in probing top quark electroweak couplings. These couplings are natural places for new phenomena to happen in the top quark sector of the standard model. Yet, they are the least explored directly. One has to obtain a firm understanding of the modeling of sensitive distributions to new top-Z interactions. The present analysis marks a major milestone in this long-term effort. All distributions relevant for new phenomena, and/or modeling of tZq, are studied in full depth using advanced Machine Learning techniques.The luminosity and its uncertainty contributes to every physics result of the experiment. The method minutely developed in this thesis provides a complementary measurement that results in a significant overall reduction of uncertainties.

Time, space and entanglement are the main characters in this book. Their nature is still a great mystery in physics and we study here the possibility that these three phenomena are closely connected, showing how entanglement can be at the basis of the emergence of time and space within closed quantum systems. We revisit and extend the Page and Wootters theory that was originally introduced in order to describe the emergence of time through entanglement between subsystems in a globally static, quantum Universe. In the book, after providing a complete review of the salient aspects of the theory, we establish a connection with recent research on the foundations of statistical mechanics and we provide a new understanding of the thermalization process. Furthermore, we generalize the framework in order describe the spatial degree of freedom and we provide a model of 3+1 dimensional, quantum spacetime emerging from entanglement among different subsystems in a globally "timeless" and "positionless" Universe. Finally, via the Page and Wootters theory, the evolution of quantum clocks within a gravitational field is treated and a time dilation effect is obtained in agreement with the Schwarzschild solution.

This book presents the experimental development of an information-powered engine inspired by the famous thought experiment, Maxwell¿s demon, to understand its potential to produce energy for practical purposes. The development of an engine based on Maxwell¿s demon was for a long time inconceivable, but technological advances have led to novel investigations into theoretical and practical applications. The built information engine consists of a micron-sized glass bead trapped in a tightly focused laser beam. It rectifies the bead's Brownian motion by controlling the laser's position and generates a unidirectional motion against gravity without doing any work, thus converting thermal heat into stored gravitational potential energy. A theoretical model based on a spring-mass system describes the engine's dynamics and was then used to find optimum parameters to improve the engine's performance. Experimentally implementing these optimization strategies led to engine output powers comparable to those measured in biological motors. This book also highlights performance improvements made in the presence of measurement noise and presents important guiding principles to design information engines to operate in non-equilibrium environments. By focusing on practical applications, the book overall aims to broaden the scope of information-engine investigations.

In recent decades, twistor theory has grown into an irreplaceable tool for the study of scattering amplitudes in gauge theory and gravity. This book introduces the reader to cutting-edge advances in twistor theory and its applications to general relativity. The problem of graviton scattering in four dimensions is shown to be dual to dramatically simpler computations in a two-dimensional CFT known as a twistor sigma model. Twistor sigma models are the first step toward a holographic description of gravity in asymptotically flat space-times. They underpin the infinitely many asymptotic symmetries of flat space physics discovered in celestial holography, and extend them to exciting new arenas like curved space-times. They also yield intrinsically mathematical results in the field of hyperkähler manifolds. This volume will be of broad interest to students and researchers looking for an accessible entry point into twistor geometry, scattering amplitudes, and celestial holography. It will also provide an invaluable reference for specialists by bringing together results from a host of different disciplines.

One of the main unanswered question of modern Physics is "How does gravity behave at small scales?". The aim of this thesis is to illustrate in a comprehensive but accessible way how to look for deviations from Einstein's theory of General Relativity in this regime, looking at the simplest celestial bodies: static and spherically symmetric ones.With a conservative and bottom-up approach, at smaller scales the first corrections to the action of General Relativity are generally considered to be terms quadratic in the curvature tensors; while these modifications do not cure the inconsistency between gravity and quantum mechanics, the solutions of this theory are plausible candidates to be the first-order corrections of the classical ones.Even with such simple modifications, a striking picture emerges from the study of isolated objects: the unique Schwarzschild solution of General Relativity is only a rare bird in the set of solutions, with non-Schwarzschild black holes, wormholes and naked singularities appearing as possible substitutes.Tailored to graduate students and researchers entering this field, this thesis shows how to construct these new solutions from action principles, how to characterize their metric, how to study their physical properties, such as their stability or Thermodynamics, and how to look for phenomenological signatures.

This book provides a comprehensive overview of Nuclear Magnetic Resonance (NMR) theory, its applications, and advanced techniques to improve the quality and speed of NMR data acquisition. In this book, the author expands his outstanding Ph.D. thesis and provides a valuable resource for researchers, professionals, and students in the field of NMR spectroscopy.The book covers quantum mechanics basics, and topics like density operators, pulse sequences, 1D pulse acquisition, INEPT (Insensitive nuclei enhancement by polarization transfer), product operators, and 2D NMR principles. It also explores innovative experiments like States HSQC (Heteronuclear Single Quantum Coherence) and echo-antiecho HSQC with gradients.In the subsequent chapters, the author discusses Pure Shift NMR, including PSYCHE (Pure Shift Yielded by Chirp Excitation) and its optimizations, such as waveform parameterization and time-reversal methods. The 'Discrete PSYCHE' approach and Ultrafast PSYCHE-iDOSY (Diffusion-ordered spectroscopy) are also highlighted.This book presents the POISE (Parameter Optimisation by Iterative Spectral Evaluation) software for real-time NMR experiment optimization, including pulse width calibration and Ernst angle optimization, and demonstrates applications across various NMR experiments.Lastly, the book examines accelerated 2D NMR data collection and the NOAH (NMR by Ordered Acquisition using 1H detection) supersequences, emphasizing automated pulse program creation using GENESIS (GENEration of Supersequences In Silico). Covered NMR experiments include 13C sensitivity-enhanced HSQC, 15N HMQC (Heteronuclear Multiple Quantum Coherence), dual HSQC, HSQC-TOCSY (Total Correlation Spectroscopy), HMBC (Heteronuclear Multiple Bond Correlation), and ADEQUATE (Adequate Sensitivity Double-Quantum Spectroscopy).

This book presents a complete study of natural orbitals in quantum impurity problems, revealing a certain simplicity in these interacting many-body problems. These systems consist of a few localized degrees of freedom that undergo strong interactions and hybridize with a larger system of free particles; they are central in the study of strongly correlated systems. In a first step, the standard non-perturbative numerical renormalization group method is employed to demonstrate the hierarchical structure of correlations unveiled by natural orbitals. This simplification brought new insights for simulating quantum impurity problems, and a new algorithm is developed to generate an optimized subset of natural orbitals independently of existing methods, going beyond their usual limitations. This algorithm is presented in detail in the book, and a careful benchmark on known results is carried out to guarantee the validity of the method. It is then used to study spatial entanglement structures under various conditions that were not accessible with previous methods, such as representing the electron bath by a realistic 2D square lattice or taking account of static disorder in the metallic host. In the last chapter, the non-interacting problem in the presence of disorder is studied through random matrix theory, reproducing some of the results presented in the previous chapters. The main original result of this chapter lies in the analytical calculation of the joint distribution of one-particle orbitals energies and amplitudes of the impurity, which makes it possible to calculate any disordered averaged local correlation functions. Starting from this result, calculations in the large-N limit are compared with numerical simulations.

This book details a new and ground-breaking contribution to the search for a successor to the Standard Model (SM) of particle physics - the largest modern endeavour in the field. In the hope of seeing a discrepancy with the SM's predictions, this work discusses two hitherto unforeseen measurements at the frontier of experimental precision: a measurement of W-boson mass and a test of the fundamental axiom of the W boson's lepton flavour universality (LFU). Both measurements are made by analysing collision data from the LHCb experiment at the Large Hadron Collider (LHC) at CERN, and represent the establishment of a new field of high-precision Standard Model tests with LHCb. This book also describes the development of new software tools for the optimisation of the LHCb trigger system, which helps to ensure that LHCb's exciting physics program can continue to prosper into the future. This book is accessible to those with graduate¿or master's¿level training in experimental particle physics.

This thesis describes how the rich internal degrees of freedom of molecules can be exploited to construct the first ¿clock¿ based on ultracold molecules, rather than atoms. By holding the molecules in an optical lattice trap, the vibrational clock is engineered to have a high oscillation quality factor, facilitating the full characterization of frequency shifts affecting the clock at the hertz level. The prototypical vibrational molecular clock is shown to have a systematic fractional uncertainty at the 14th decimal place, matching the performance of the earliest optical atomic lattice clocks. As part of this effort, deeply bound strontium dimers are coherently created, and ultracold collisions of these Van der Waals molecules are studied for the first time, revealing inelastic losses at the universal rate. The thesis reports one of the most accurate measurements of a molecule¿s vibrational transition frequency to date. The molecular clock lays the groundwork for explorations into terahertz metrology, quantum chemistry, and fundamental interactions at atomic length scales.

This book describes the development of novel protein¿RNA-binding assays and their applications in a high-throughput manner for the identification of small-molecule modulators of protein¿RNA interactions to treat cancer and COVID-19.Modulating protein¿RNA interactions with small molecules is expected to provide novel biological insights of the interrelation of diseases with the protein¿RNA interactome. The modulations may also be exploited therapeutically. For these reasons, the development of a simple, reliable, and sensitive protein¿RNA-binding assay is necessary for high-throughput screening to discover new effective chemical entities capable of acting on diverse protein¿RNA interactions. This book discusses the discovery of small-molecule modulators targeting protein¿RNA interactions that are potentially valuable to treat cancer and COVID-19 by constructing novel high-throughput screening methods. The results of this dissertation provide valuable insights into the regulation of protein¿RNA interactions in chemical biology and drug development.

This thesis outlines the principles, device physics, and technological applications of electronics based on the ultra-wide bandgap semiconductor aluminum nitride. It discusses the basic principles of electrostatics and transport properties of polarization-induced two-dimensional electron and hole channels in semiconductor heterostructures based on aluminum nitride. It explains the discovery of high-density two-dimensional hole gases in undoped heterojunctions, and shows how these high conductivity n- and p-type channels are used for high performance nFETs and pFETs, along with wide bandgap RF, mm-wave, and CMOS applications. The thesis goes on to discuss how the several material advantages of aluminum nitride, such as its high thermal conductivity and piezoelectric coefficient, enable not just high performance of transistors, but also monolithic integration of passive elements such as high frequency filters, enabling a new form factor for integrated RF electronics.

In this thesis, the author proposes "metal-responsive base pair switching" of ligand-modified nucleobases as a novel tool for stimuli-responsive control of DNA assemblies. It is written to demonstrate broad applicability of the base pair switching in dynamic DNA nanotechnology and inspire researchers to use this technique. Based on specific interactions between ligand-type nucleobases and target metal ions, in this volume, DNA hybridization was dynamically controlled through strand displacement reactions. The base pair switching was further applied to develop metal-dependent DNA molecular machines. This novel strategy for stimuli-responsive regulation of DNA assemblies will greatly expand the scope of dynamic DNA nanotechnology. This volume uniquely features importance of elaborate molecular design based on chemistry for imparting stimuli responsiveness to DNA assemblies.

This book presents novel observational evidence toward detecting and characterizing the products of massive, interacting binary stars. As a majority of massive stars are born in close binary systems, a large number of so-called massive binary interaction products are predicted to exist; however, few have been identified so far. Based on observations with the largest telescopes around the world, equipped with state-of-the-art instrumentation, this book helps to remedy this situation. In her outstanding PhD-thesis Julia Bodensteiner identifies a new class of post-interaction binaries in a short-lived phase just briefly after the initially more massive star has been stripped of part of its envelope. She further provides new evidence for the Be phenomenon to largely result from binary interactions. These results represented a new and testable prediction for the evolution of these stars and opened up a new way forward for identifying hundreds of post-interaction products.Finally, using the MUSE integral field spectrograph at the Very Large Telescope in Chile, the author presents a novel spectroscopic campaign focusing on the 40 Myr-old star cluster NGC 330 in the Small Magellanic Clouds. Combined with photometric observations from the Hubble Space Telescope, the MUSE data allow to characterize the entire massive star population of NGC 330, revealing their multiplicity properties and rotational velocities and providing unique observational constraints on their (binary) evolution history. This is made possible by the developments of novel numerical methods allowing to extract star spectra from the MUSE integral field spectroscopic data and to characterize their properties by the simultaneous comparison of MUSE spectroscopy and Hubble photometry with atmospheric models.This book is a partly re-written version of the author's thesis offering a highly readable coherent text presenting not only new insights into the properties of binary interaction products but also giving students an excellent introduction into the field.