This thesis covers a diverse set of topics related to space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). The core of the thesis is devoted to the preprocessing of the interferometric link data for a LISA constellation, specifically developing optimal Kalman filters to reduce arm length noise due to clock noise. The approach is to apply Kalman filters of increasing complexity to make optimal estimates of relevant quantities such as constellation arm length, relative clock drift, and Doppler frequencies based on the available measurement data. Depending on the complexity of the filter and the simulated data, these Kalman filter estimates can provide up to a few orders of magnitude improvement over simpler estimators. While the basic concept of the LISA measurement (Time Delay Interferometry) was worked out some time ago, this work brings a level of rigor to the processing of the constellation-level data products. The thesis concludes with some topics related to the eLISA such as a new class of phenomenological waveforms for extreme mass-ratio inspiral sources (EMRIs, one of the main source for eLISA), an octahedral space-based GW detector that does not require drag-free test masses, and some efficient template-search algorithms for the case of relatively high SNR signals.

This book provides a chronological introduction to modern atomic theory, which represented an attempt to reconcile the ancient doctrine of atomism with careful experiments-performed during the 19th century-on the flow of heat through substances and across empty space. Included herein are selections from classic texts such as Carnot's Reflection on the Motive Power of Fire, Clausius' Mechanical Theory of Heat, Rutherford's Nuclear Constitution of Atoms, Planck's Atomic Theory of Matter and Heisenberg's Copenhagen Interpretation of Quantum Theory. Each chapter begins with a short introduction followed by a reading selection. Carefully crafted study questions draw out key points in the text and focus the reader's attention on the author's methods, analysis and conclusions. Numerical and laboratory exercises at the end of each chapter test the reader's ability to understand and apply key concepts from the text. Heat, Radiation and Quanta is the last of four volumes in A Student's Guide through the Great Physics Texts. The book comes from a four-semester undergraduate physics curriculum designed to encourage a critical and circumspect approach to natural science while at the same time preparing students for advanced coursework in physics. This book is particularly suitable as a college-level textbook for students of the natural sciences, history or philosophy. It might also serve as a textbook for advanced high-school or home-schooled students, or as a thematically-organized source-book for scholars and motivated lay-readers. In studying the classic scientific texts included herein, the reader will be drawn toward a lifetime of contemplation.

This book presents an overview of the current understanding of gravitation, with a focus on the current efforts to test its theory, especially general relativity. It shows how the quest for a deeper theory, which would possibly incorporate gravity in the quantum realm, is more than ever an open field. The majority of the contributions deals with the manifold facets of "experimental gravitation", but the book goes beyond this and covers a broad range of subjects from the foundations of gravitational theories to astrophysics and cosmology. The book is divided into three parts. The first part deals with foundations and Solar System tests. An introductory pedagogical chapter reviews first Newtonian gravitational theory, special relativity, the equivalence principle and the basics of general relativity. Then it focuses on approximation methods, mainly the post-Newtonian formalism and the relaxed Einstein equations, with a discussion on how they are used in treating experimental tests and in the problem of generation and detection of gravitational waves. Following this is a set of chapters describing the most recent experiments, techniques and observations on the testing of gravity theories in the laboratory, around the Earth and in the Solar System. The second part is dedicated to astrophysical topics deeply linked with the study of gravitation, namely binary pulsars and the perspective of direct detection of gravitational waves. These cases are paradigmatic in that the gravitational signals act at the same time as messengers helping us to understand the properties of important and wide classes of astrophysical objects. The third part explores the many open issues in current knowledge of gravitation machinery, especially related to astrophysical and cosmological problems and the way possible solutions to them impact the quest for a quantum theory of gravitation and unified theory. Included is a selection of the many possible paths, giving a hint to the subtleties one is called upon. Whenever possible, a close link to observational constraints and possible experimental tests is provided. In selecting the topics of the various contributions, particular care has been devoted to ensure their fit in a coherent representation of our understanding of gravitational phenomena. The book is aimed at graduate level students and will form a valuable reference for those working in the field.

This thesis sheds valuable new light on the second-order cosmological perturbation theory, extensively discussing it in the context of cosmic microwave background (CMB) fluctuations. It explores the observational consequences of the second-order vector mode, and addresses magnetic field generation and the weak lensing signatures, which are key phenomena of the vector mode. The author demonstrates that the second-order vector mode, which never appears at the linear-order level, naturally arises from the non-linear coupling of the first-order scalar modes. This leads to the remarkable statement that the vector-order mode clearly contributes to the generation of cosmological magnetic fields. Moreover, the weak lensing observations are shown to be accessible to the vector mode. On the basis of ongoing and forthcoming observations, the thesis concludes that the second-order vector mode is detectable.

This thesis focuses on understanding the growth and formation mechanism of supermassive black holes (SMBHs), an issue it addresses by investigating the dense interstellar medium that is assumed to be a crucial component of the fuel for SMBHs. The thesis also offers unique guidance on using the Atacama Large Millimeter/submillimeter Array (ALMA) in active galactic nuclei (AGN) research. The author presents the three major findings regarding SMBH formation and growth: (1) The development of a new diagnostic method for the energy sources in galaxies based on submillimeter spectroscopy, which allows identification of accreting SMBHs even in obscured environments, (2) the discovery that the circumnuclear dense gas disk (CND), with a typical size of a few tens of parsecs, which plays a crucial role in governing the growth of SMBHs, and (3) the discovery that the mass transfer budget from the CND to the central SMBHs can be quantitatively understood with a theoretical model incorporating the circumnuclear starburst as a driver of mass transfer. The thesis skillfully reviews these three findings, which have greatly improved our understanding of the growth mechanism of SMBHs.

This book presents the author's personal historical perspective and conceptual analysis on symmetry and geometry. The author enlightens with modern views the historical process which led to the contemporary vision of space and symmetry that are used in theoretical physics and in particular in such abstract and advanced descriptions of the physical world as those provided by supergravity. The book is written intertwining storytelling and philosophical argumentation with some essential technical material. The author argues that symmetry and geometry are inextricably entangled and their current meaning is the result of a long process of abstraction which was determined through history and can be understood within the analytic system of thought of western civilization that started with the Ancient Greeks. The evolution of geometry and symmetry theory in the last forty years has been deeply and constructively influenced by supersymmetry/supergravity and the allied constructions of strings and branes. Further advances in theoretical physics cannot be based simply on the Galilean method of interrogating nature and then formulating a testable theory to explain the observed phenomena. One ought to interrogate human thought, meaning frontier-line mathematics concerned with geometry and symmetry in order to find there the threads of so far unobserved correspondences, reinterpretations and renewed conceptions.

What is spectral action, how to compute it and what are the known examples? This book offers a guided tour through the mathematical habitat of noncommutative geometry a la Connes, deliberately unveiling the answers to these questions. After a brief preface flashing the panorama of the spectral approach, a concise primer on spectral triples is given. Chapter 2 is designed to serve as a toolkit for computations. The third chapter offers an in-depth view into the subtle links between the asymptotic expansions of traces of heat operators and meromorphic extensions of the associated spectral zeta functions. Chapter 4 studies the behaviour of the spectral action under fluctuations by gauge potentials. A subjective list of open problems in the field is spelled out in the fifth Chapter. The book concludes with an appendix including some auxiliary tools from geometry and analysis, along with examples of spectral geometries. The book serves both as a compendium for researchers in the domain of noncommutative geometry and an invitation to mathematical physicists looking for new concepts.

This book discusses the upgrade of the Super-Kamiokande (SK) detector, which consists in the addition of a salt of gadolinium into the detector's water, the goal being to endow it with a very high-efficiency ability to detect neutrons: the SuperK-Gd project. This will substantially improve the scientific value of the SK detector because, among others, neutron production is related to the matter-antimatter character of the interacting neutrino. In this book the authors develop several procedures for maximizing the impact of neutron tagging in various physics analyses involving a broad range of neutrino energy. They thoroughly study the impact of new backgrounds introduced by Gd in key physics analyses, most remarkably including the search for the Diffuse Supernova Neutrino Background. At GeV energies, the neutron tagging improvements are evaluated by performing a complete neutrino oscillation sensitivity study using atmospheric and long baseline neutrinos, with a focus on the neutrino mass hierarchy and the leptonic CP violation. In order to prove the relevance of neutron tagging with the available data, the authors apply the neutron-tagging tools developed here to the 4th phase of the SK detector, which is already capable of detecting a low fraction of the neutrons produced through hydrogen-neutron captures. A global oscillation analysis of the SK's atmospheric neutrino data is also conducted.

This book explores the use of numerical relativity (NR) methods to solve cosmological problems, and describes one of the first uses of NR to study inflationary physics. NR consists in the solution of Einstein's Equation of general relativity, which governs the evolution of matter and energy on cosmological scales, and in systems where there are strong gravitational effects, such as around black holes. To date, NR has mainly been used for simulating binary black hole and neutron star mergers like those detected recently by LIGO. Its use as a tool in fundamental problems of gravity and cosmology is novel, but rapidly gaining interest. In this thesis, the author investigates the initial condition problem in early universe cosmology - whether an inflationary expansion period could have "got going" from initially inhomogeneous conditions - and identifies criteria for predicting the robustness of particular models. State-of-the-art numerical relativity tools are developed in order to address this question, which are now publicly available.

This book, designed as a tool for young researchers and graduate students, reviews the main open problems and research lines in various fields of astroparticle physics: cosmic rays, gamma rays, neutrinos, cosmology, and gravitational physics. The opening section discusses cosmic rays of both galactic and extragalactic origin, examining experimental results, theoretical models, and possible future developments. The basics of gamma-ray astronomy are then described, including the detection methods and techniques. Galactic and extragalactic aspects of the field are addressed in the light of recent discoveries with space-borne and ground-based detectors. The review of neutrinos outlines the status of the investigations of neutrino radiation and brings together relevant formulae, estimations, and background information. Three complementary issues in cosmology are examined: observable predictions of inflation in the early universe, effects of dark energy/modified gravity in the large-scale structure of the universe, and neutrinos in cosmology and large-scale structures. The closing section on gravitational physics reviews issues relating to quantum gravity, atomic precision tests, space-based experiments, the strong field regime, gravitational waves, multi-messengers, and alternative theories of gravity.

This is the second and final volume of Dutch physicist Hendrik Antoon Lorentz's scientific correspondence with Dutch colleagues, including Pieter Zeeman and Paul Ehrenfest. These 294 letters cover multiple subjects, ranging from pure mathematics to magneto-optics and wave mechanics. They reveal much about their author, including Lorentz's surprisingly active involvement in experimental matters in the first decades of his career. Letters are also devoted to general relativity, Lorentz's 1908 lecture on radiation theory, and his receipt of the Nobel Prize along with Zeeman in 1902. The letters are presented in their original language; Dutch originals are accompanied by English translations. A concise biography of Lorentz is also included.

Topological surgery is a mathematical technique used for creating new manifolds out of known ones. In this book the authors observe that it also occurs in natural phenomena of all scales: 1-dimensional surgery happens during DNA recombination and when cosmic magnetic lines reconnect; 2-dimensional surgery happens during tornado formation and cell mitosis; and they conjecture that 3-dimensional surgery happens during the formation of black holes from cosmic strings, offering an explanation for the existence of a black hole's singularity. Inspired by such phenomena, the authors present a new topological model that extends the formal definition to a continuous process caused by local forces. Lastly, they describe an intrinsic connection between topological surgery and a chaotic dynamical system exhibiting a "hole drilling" behavior. The authors' model indicates where to look for the forces causing surgery and what deformations should be observed in the local submanifolds involved. These predictions are significant for the study of phenomena exhibiting surgery and they also open new research directions. This novel study enables readers to gain a better understanding of the topology and dynamics of various natural phenomena, as well as topological surgery itself and serves as a basis for many more insightful observations and new physical implications.

This book focuses on the development and implementation of the longitudinal, angular and frequency controls of the Advanced Virgo detector, both from the simulation and experimental point of view, which contributed to Virgo reaching a sensitivity that enabled it to join the LIGO-Virgo O2 run in August 2017. This data taking was very successful, with the first direct detection of a binary black hole merger (GW170814) using the full network of three interferometers, and the first detection and localization of a binary neutron star merger (GW170817). The second generation of gravitational wave detector, Advanced Virgo, is capable of detecting differential displacements of the order of 10-21m. This means that it is highly sensitive to any disturbance, including the seismic movement of the Earth. For this reason an active control is necessary to keep the detector in place with sufficient accuracy.

This book employs computer simulations of 'artificial' Universes to investigate the properties of two popular alternatives to the standard candidates for dark matter (DM) and dark energy (DE). It confronts the predictions of theoretical models with observations using a sophisticated semi-analytic model of galaxy formation. Understanding the nature of dark matter (DM) and dark energy (DE) are two of the most central problems in modern cosmology. While their important role in the evolution of the Universe has been well established-namely, that DM serves as the building blocks of galaxies, and that DE accelerates the expansion of the Universe-their true nature remains elusive. In the first half, the authors consider 'sterile neutrino' DM, motivated by recent claims that these particles may have finally been detected. Using sophisticated models of galaxy formation, the authors find that future observations of the high redshift Universe and faint dwarf galaxies in the Local Group can place strong constraints on the sterile neutrino scenario. In the second half, the authors propose and test novel numerical algorithms for simulating Universes with a 'modified' theory of gravity, as an alternative explanation to accelerated expansion. The authors' techniques improve the efficiency of these simulations by more than a factor of 20 compared to previous methods, inviting the readers into a new era for precision cosmological tests of gravity.

This book discusses searches for Dark Matter at the CERN's LHC, the world's most powerful accelerator. It introduces the relevant theoretical framework and includes an in-depth discussion of the Effective Field Theory approach to Dark Matter production and its validity, as well as an overview of the formalism of Simplified Dark Matter models. Despite overwhelming astrophysical evidence for Dark Matter and numerous experimental efforts to detect it, the nature of Dark Matter still remains a mystery and has become one of the hottest research topics in fundamental physics. Two searches for Dark Matter are presented, performed on data collected with the ATLAS experiment. They analyze missing-energy final states with a jet or with top quarks. The analyses are explained in detail, and the outcomes and their interpretations are discussed, also in view of the precedent analysis of theoretical approaches. Given its depth of coverage, the book represents an excellent reference guide for all physicists interested in understanding the theoretical and experimental considerations relevant to Dark Matter searches at the LHC.

This book provides a number of combinatorial tools that allow a systematic study of very general discrete spaces involved in the context of discrete quantum gravity. In any dimension D, we can discretize Euclidean gravity in the absence of matter over random discrete spaces obtained by gluing families of polytopes together in all possible ways. These spaces are then classified according to their curvature. In D=2, it results in a theory of random discrete spheres, which converge in the continuum limit towards the Brownian sphere, a random fractal space interpreted as a quantum random space-time. In this limit, the continuous Liouville theory of D=2 quantum gravity is recovered. Previous results in higher dimension regarded triangulations, converging towards a continuum random tree, or gluings of simple building blocks of small sizes, for which multi-trace matrix model results are recovered in any even dimension. In this book, the author develops a bijection with stacked two-dimensional discrete surfaces for the most general colored building blocks, and details how it can be used to classify colored discrete spaces according to their curvature. The way in which this combinatorial problem arrises in discrete quantum gravity and random tensor models is discussed in detail.

When predictions of Einstein's theory of General Relativity are compared against observations of our Universe, a huge inconsistency is found. The most popular fix for this inconsistency is to "invent" around 94% of the content of the universe: dark matter and dark energy. The dark energy is some exotic substance responsible for the apparent observed acceleration of the Universe. Another fix is to modify the theory of gravity: it is entirely plausible that Einstein's theory of General Relativity breaks down on cosmological scales, just as Newton's theory of gravity breaks down in the extreme gravitational field of the Sun. There are many alternative theories of gravity, each with the aim of describing observations of our Universe where General Relativity fails. Whether it is dark energy or some modified theory of gravity, it is clear that there is some "dark sector" in the Universe. In this thesis the author constructs a unifying framework for understanding the observational impact of general classes of dark sector theories, by formulating equations of state for the dark sector perturbations.

The successes of the standard models of particle physics and cosmology are many, but have proven incapable of explaining all the phenomena that we observe. This book investigates the potentially important role of quantum physics, particularly quantum anomalies, in various aspects of modern cosmology, such as inflation, the dynamical generation of the visible and dark matter in the universe, and gravitational waves. By doing so, the authors demonstrate that exploring the links between cosmology and particle physics is key to helping solve the mysteries of our Universe.

This book presents the proceedings of the 2nd Karl Schwarzschild Meeting on Gravitational Physics, focused on the general theme of black holes, gravity and information.Specialists in the field of black hole physics and rising young researchers present the latest findings on the broad topic of black holes, gravity, and information, highlighting its applications to astrophysics, cosmology, particle physics, and strongly correlated systems.

A self-contained text, systematically presenting the determination and classification of exact solutions in three-dimensional Einstein gravity. This book explores the theoretical framework and general physical and geometrical characteristics of each class of solutions, and includes information on the researchers responsible for their discovery. Beginning with the physical character of the solutions, these are identified and ordered on the basis of their geometrical invariant properties, symmetries, and algebraic classifications, or from the standpoint of their physical nature, for example electrodynamic fields, fluid, scalar field, or dilaton. Consequently, this text serves as a thorough catalogue on 2+1 exact solutions to the Einstein equations coupled to matter and fields. The solutions are also examined from different perspectives, enabling a conceptual bridge between exact solutions of three- and four-dimensional gravities, and therefore providing graduates and researchers with an invaluable resource on this important topic in gravitational physics. Including contributions by David Chow, Christopher N. Pope and Ergin Sezgin (chapters 16-19).

Reprint of a classical book first published in 1950. This lucid and profound exposition of Einstein's 1915 theory of gravitation is essential reading.

This thesis addresses two very different but equally important topics in the very broad fields of astrophysics and cosmology: (I) the generation of cosmological magnetic fields and (II) gravitational fragmentation of the Cosmic Web. All mathematical developments are completed by illuminating physical interpretations, and the thesis, which is guided by existing observations, is purely theoretical. In part I, the author further develops a magnetogenesis model proposed in the literature, providing an unprecedented level of physical understanding. He demonstrates that the physics of photoionisation is very likely to have premagnetised, at a relevant level, the entire Universe at the early epoch of the formation of the first luminous sources. In part II, the author adapts the tools of plasma spectral theory to the context of gravitational instability of the baryonic gas within the stratified structures of the Cosmic Web. He skillfully derives the wave equation governing the growth of perturbations and explores various equilibrium configurations, in planar and cylindrical geometries characteristic of cosmic walls and filaments, for isothermal and polytropic conditions, with or without an external gravitational background. Clearly structured and written in pedagogical style, this outstanding thesis puts the results into perspective and highlights the merits and limitations of the various approaches explored.

This thesis explores the possibility of searching for new effects of dark matter that are linear in g, an approach that offers enormous advantages over conventional schemes, since the interaction constant g is very small, g<<1. Further, the thesis employs an investigation of linear effects to derive new limits on certain interactions of dark matter with ordinary matter that improve on previous limits by up to 15 orders of magnitude. The first-ever limits on several other interactions are also derived. Astrophysical observations indicate that there is five times more dark matter-an 'invisible' form of matter, the identity and properties of which still remain shrouded in mystery-in the Universe than the ordinary 'visible' matter that makes up stars, planets, dust and interstellar gases. Conventional schemes for the direct detection of dark matter involve processes (such as collisions with, absorption by or inter-conversion with ordinary matter) that are either quartic (g4) or quadratic (g2) in an underlying interaction constant g.