The author describes superfluidity as the jewel in the crown of low temperature physics. At low enough temperatures, every substance in thermal equilibrium must become ordered. Since some materials remain fluid to the lowest temperatures, it is a fascinating question as to how this ordering can take place. One possibility is the formation of a superfluid state, a state in which there is macroscopic quantum order, effectively quantum mechanics in a tea-cup. These ideas are developed in chapter 1. The book assumes some basic knowledge of quantum, statistical and thermal physics, and builds on this background to give a readable introduction to the three superfluids of low temperature physics.
A short chapter describing experimental techniques is included. The emphasis throughout is on physical principles rather than technical detail, with the aim of introducing the subject in an accessible yet authoritative way to final year undergraduates or starting postgraduate students.

Most previous texts on quantum optics have been written primarily for the graduate student market at PhD level and above. Quantum optics: an introduction aims to introduce a wide range of topics at a lower level suitable for advanced undergraduate and masters level students in physics. The
text is divided into four main parts, covering modern topics in both pure and applied quantum optics: I Introduction and background material. II. Photons. III. Atom-photon interactions. IV. Quantum information processing. The emphasis of the subject development is on intuitive physical
understanding rather than mathematical arguments, although many derivations are included where appropriate. The text includes numerous illustrations, with a particular emphasis on the experimental observations of quantum optical phenomena. Each chapter includes worked examples, together with 10-15
exercises with solutions. Six appendices are included to supplement the main subject material.

This fourth edition is primarily aimed at helping physicists, physical chemists, materials scientists, metallurgists, engineers, and biologists to carry out investigations at low temperatures. This new edition takes into account the major changes in cryogenic technology over the past twenty years. These changes include areas of temperature measurement and control, superconducting magnets, cryocoolers, ultra-low temperatures, technical data on materials, commercially available cryostats for optical, x-ray, thermal and electrical measurements. Less emphasis is now placed on methods of constructing cryostats in the laboratory and more emphasis on commercially available cryostats, temperature controllers, and closed circuit cryocoolers. The book contains comprehensive, up-to-date tables of physical property data on metals, polymers, and ceramics. It will be of value to graduate students as well as to engineers and biologists facing cryogenic problems.

This book describes collisions between atoms that have been cooled to extremely low temperatures by optical and evaporative cooling techniques. John Weiner reviews the elements of the quantum theory of scattering, and summarizes the theory and experimental techniques of optical cooling and trapping. He also describes applications to precision spectroscopy, the determination of atomic properties, control of inelastic collisions by laser fields, and the manipulation of Bose-Einstein condensates (mesoscopic quantum systems).

This book introduces readers to the characteristic features of electromagnetic phenomena in superconductivity. It first demonstrates not only that the diamagnetism in the superconductivity complies with Maxwell's theory, which was formulated before the discovery of superconductivity, but also that the dominant E-B analogy in the electromagnetism loses perfection without the superconductivity. The book then explores flux pinning, which is responsible for the non-dissipative current in DC, leading to irreversibility in AC. Drawing on Maxwell's work, it also proves theoretically that if there is no energy dissipation in the superconductivity caused by the break in time reversal symmetry, it contradicts the thermodynamic principle of energy conservation - something that had previously only been proved experimentally. Lastly, the book addresses the longitudinal magnetic field effect, and explains how this phenomenon leads to a new development of Maxwell's theory. Featuring numerous appendices to help readers understand the methods of derivation of equations, this book offers students and young scientists an introduction to applied superconductivity, especially in the context of power applications. Presenting the characteristic features of electromagnetic phenomena in superconductivity from basic to advanced topics for applications, the book offers a valuable resource for graduate students and researchers studying superconductivity as well as engineers working in electric utility industry.

This book presents the basics of superconductivity and applications of superconducting magnets. It explains the phenomenon of superconductivity, describes theories of superconductivity, and discusses type II and high-temperature cuprate superconductors. The main focus of the book is the application of superconducting magnets in accelerators, fusion reactors and other advanced applications such as nuclear magnetic resonance (NMR), magnetic resonance imaging (MRI), high-gradient magnetic separation (HGMS), and superconducting magnetic energy storage (SMES). This new and significantly extended second edition covers the state of the art in the development of novel superconductors for advanced magnet applications, as well as the production of practical superconducting wires, tapes, and ultra high current cables used for high-field magnets. It includes two new chapters each devoted to MgB2 and Fe-based superconductors, and discusses the recently developed and world record-setting 45.5-Tesla magnetic field generated by a combination of conventional and high-temperature cuprate superconducting magnets. In addition, it discusses the status and outlook of all current and future nuclear fusion reactors worldwide. The chapter on accelerators includes the ongoing efforts to build high luminosity LHC (HL-LHC), the high-energy 28 TeV LHC (HE-LHC), the future circular collider (FCC) at CERN, and the just launched electro-ion collider (EIC) at Brookhaven National Laboratory. The book is based on the long-standing experience of the author in studying superconducting materials, building magnets and delivering numerous lectures to research scholars and students. The book provides comprehensive and fundamental knowledge in the field of applied superconductivity, greatly benefiting researchers and graduate students wishing to learn more about the various aspects of superconductivity and advanced magnet applications.

This book offers a practical introduction to helium refrigeration engineering, taking a logical and structured approach to the design, building, commissioning, operation and maintenance of refrigeration systems. It begins with a short refresher of cryogenic principles, and a review of the theory of heat exchangers, allowing the reader to understand the importance of the heat exchanger role in the various thermodynamic cycle structures. The cycles are considered from the simplest (Joule Thomson) to the most complicated ones for the very large refrigeration plants and, finally, those operating at temperatures lower than 4.5 K. The focus then turns to the operation, ability and limitations of the main components, including room temperature cycle screw compressors, heat exchangers, cryogenic expansion turbines, cryogenic centrifugal compressors and circulators. The book also describes the basic principles of process control and studies the operating situations of helium plants, with emphasis on high level efficiency. A major issue is helium purity, and the book explains why helium is polluted, how to purify it and then how to check its purity, to ensure that all components are filled with pure helium prior to starting. Although the intention of the book is not to design thermodynamic cycles, it is of interest to a designer or operator of a cryogenic system to perform some simplified calculations to get an idea of how components or systems are behaving. Throughout the book, such calculations are generally performed using Microsoft (R) Excel and the Gaspak (R) or Hepak (R) software.

This thesis presents the first ever measurement of the noise emitted by magnetic monopoles and the development of an exquisitely sensitive magnetic-field-noise spectrometer based on a superconducting quantum interference device (SQUID) that enabled it. Magnetic monopoles are highly elusive elementary particles exhibiting quantized magnetic charge. The prospects for studying them brightened recently with the theoretical discovery that the thermally excited states in certain classes of magnetic insulators exhibit all the characteristics of magnetic monopoles. Furthermore, in 2018, it was predicted that the random motion of magnetic monopoles inside would generate a very specific kind of magnetization noise. In this thesis, the author describes a new experimental technique, so-called spin noise spectroscopy, and the subsequent discovery of virtually all of the predicted features of the magnetic noise expected from a dense fluid of magnetic monopoles in crystals of Dy2Ti2O7. Remarkably, because this magnetic monopole noise occurs in the frequency range below 20kHz, when amplified by the SQUID it is actually audible to humans.

This thesis unifies the dissipative dynamics of an atom, particle or structure within an optical field that is influenced by the position of the atom, particle or structure itself. This allows the identification and exploration of the fundamental 'mirror-mediated' mechanisms of cavity-mediated cooling leading to the proposal of a range of new techniques based upon the same underlying principles. It also reveals powerful mechanisms for the enhancement of the radiation force cooling of micromechanical systems, using both active gain and the resonance of a cavity to which the cooled species are external. This work has implications for the cooling not only of weakly-scattering individual atoms, ions and molecules, but also for highly reflective optomechanical structures ranging from nanometre-scale cantilevers to the metre-sized mirrors of massive interferometers.

The relaxation of isolated quantum many-body systems is a major unsolved problem of modern physics, which is connected to many fundamental questions. However, realizations of quantum many-body systems which are both well isolated from their environment and accessible to experimental study are scarce. In recent years, the field has experienced rapid progress, partly attributed to ultra-cold atoms. This book presents the experimental study of a relaxation phenomenon occurring in a one-dimensional bosonic Josephson junction. The system consists of two 1D quasi Bose-Einstein condensates of 87Rb, magnetically trapped on an atom chip. Using radio-frequency dressing, the author deforms a single harmonic trap, in which the atoms are initially condensed, into a double-well potential and realizes a splitting of the wave function. A large spatial separation and a tilt of the double-well enable the preparation of a broad variety of initial states by precisely adjusting the initial population and relative phase of the two wave packets, while preserving the phase coherence. By re-coupling the two wave packets, the author investigates tunneling regimes such as Josephson (plasma) oscillations and macroscopic quantum self-trapping. In both regimes, the tunneling dynamics exhibits a relaxation to a phase-locked equilibrium state contradicting theoretical predictions. The experimental results are supported with an empirical model that allows quantitative discussions according to various experimental parameters. These results illustrate how strongly the non-equilibrium dynamics differ from the equilibrium one, which is well described by thermodynamics and statistical physics.

Advancing the experimental study of superfluids relies on increasingly sophisticated techniques. We develop and demonstrate the loading of Bose-Einstein condensates (BECs) into nearly arbitrary trapping potentials, with a resolution improved by a factor of seven when compared to reported systems. These advanced control techniques have since been adopted by several cold atoms labs around the world. How this BEC system was used to study 2D superfluid dynamics is described. In particular, negative temperature vortex states in a two-dimensional quantum fluid were observed. These states were first predicted by Lars Onsager 70 years ago and have significance to 2D turbulence in quantum and classical fluids, long-range interacting systems, and defect dynamics in high-energy physics. These experiments have established dilute-gas BECs as the prototypical system for the experimental study of point vortices and their nonequilibrium dynamics. We also developed a new approach to superfluid circuitry based on classical acoustic circuits, demonstrating its conceptual and quantitative superiority over previous lumped-element models. This has established foundational principles of superfluid circuitry that will impact the design of future transport experiments and new generation quantum devices, such as atomtronics circuits and superfluid sensors.

This thesis demonstrates that an ultralow temperature refrigeration technique called "demagnetisation refrigeration" can be miniaturised and incorporated onto millimeter-sized chips to cool nanoelectronic circuits, devices and materials. Until recently, the lowest temperature ever reached in such systems was around 4 millikelvin. Here, a temperature of 1.2mK is reported in a nanoelectronic device. The thesis introduces the idea that on-chip demagnetization refrigeration can be used to cool a wide variety of nanostructures and devices to microkelvin temperatures. This brings the exciting possibility of discovering new physics, such as exotic electronic phases, in an unexplored regime and the potential to improve the performance of existing applications, including solid-state quantum technologies. Since the first demonstration of on-chip demagnetization refrigeration, described here, the technique has been taken up by other research groups around the world. The lowest on-chip temperature is currently 0.4mK. Work is now underway to adapt the technique to cool other materials and devices, ultimately leading to a platform to study nanoscale materials, devices and circuits at microkelvin temperatures.

This book serves as an introduction to cryocooler technology and describes the principle applications of cryocoolers across a broad range of fields. It covers the specific requirements of these applications, and describes how the advantages and disadvantages of different cryocooler systems are taken into consideration. For example, Stirling coolers tend to be used only in space applications because of their high coefficient of performance, low weight and proven reliability, whilst Gifford-McMahon coolers are used for ground applications, such as in cryopumps and MRI shield cooling applications. Joule-Thomson cryocoolers are used in missile technology because of the fast cool down requirements. The cryocooler field is fast developing and the number of applications are growing because of the increasing costs of the cryogens such as Helium and Neon. The first chapter of the book introduces the different types of cryocoolers, their classification, working principles, and their design aspects, and briefly mentions some of the applications of these systems. This introductory chapter is followed by a number of contributions from prominent international researchers, each describing a specific field of application, the cooling requirements and the cryocooler systems employed. These areas of application include gas liquefaction, space technology, medical science, dilution refrigerators, missile systems, and physics research including particle accelerators. Each chapter describes the cooling requirements based on the end use, the approximate cooling load calculations, the criteria for cryocooler selection, the arrangement for cryocooler placement, the connection of the cooler to the object to be cooled, and includes genuine case studies. Intended primarily for researchers working on cryocoolers, the book will also serve as an introduction to cryocooler technology for students, and a useful reference for those using cryocooler systems in any area of application.

This thesis presents results crucial to the emerging field of indirect excitons. These specially designed quasiparticles give the unique opportunity to study fundamental properties of quantum degenerate Bose gases in semiconductors. Furthermore, indirect excitons allow for the creation of novel optoelectronic devices where excitons are used in place of electrons. Excitonic devices are explored for the development of advanced signal processing seamlessly coupled with optical communication. The thesis presents and describes the author's imaging experiments that led to the discovery of spin transport of excitons. The many firsts presented herein include the first studies of an excitonic conveyer, leading to the discovery of the dynamical localization-delocalization transition for excitons, and the first excitonic ramp and excitonic diode with no energy-dissipating voltage gradient.

This book offers a compact tutorial on basic concepts and tools in quantum many-body physics, and focuses on the correlation effects produced by mutual interactions. The content is divided into three parts, the first of which introduces readers to perturbation theory. It begins with the simplest examples-hydrogen and oxygen molecules-based on their effective Hamiltonians, and looks into basic properties of electrons in solids from the perspective of localized and itinerant limits. Readers will also learn about basic theoretical methods such as the linear response theory and Green functions. The second part focuses on mean-field theory for itinerant electrons, e.g. the Fermi liquid theory and superconductivity. Coulomb repulsion among electrons is addressed in the context of high-Tc superconductivity in cuprates and iron pnictides. A recent discovery concerning hydride superconductors is also briefly reviewed. In turn, the third part highlights quantum fluctuation effects beyond the mean-field picture. Discussing the dramatic renormalization effect in the Kondo physics, it provides a clear understanding of nonperturbative interaction effects. Further it introduces readers to fractionally charged quasi-particles in one and two dimensions. The last chapter addresses the dynamical mean field theory (DMFT). The book is based on the author's long years of experience as a lecturer and researcher. It also includes reviews of recent focus topics in condensed matter physics, enabling readers to not only grasp conventional condensed matter theories but also to catch up on the latest developments in the field.

This work reports on the generation of artificial magnetic fields with ultracold atoms in optical lattices using laser-assisted tunneling, as well as on the first Chern-number measurement in a non-electronic system. It starts with an introduction to the Hofstadter model, which describes the dynamics of charged particles on a square lattice subjected to strong magnetic fields. This model exhibits energy bands with non-zero topological invariants called Chern numbers, a property that is at the origin of the quantum Hall effect. The main part of the work discusses the realization of analog systems with ultracold neutral atoms using laser-assisted-tunneling techniques both from a theoretical and experimental point of view. Staggered, homogeneous and spin-dependent flux distributions are generated and characterized using two-dimensional optical super-lattice potentials. Additionally their topological properties are studied via the observation of bulk topological currents. The experimental techniques presented here offer a unique setting for studying topologically non-trivial systems with ultracold atoms.

This thesis demonstrates a full Mach-Zehnder interferometer with interacting Bose-Einstein condensates confined on an atom chip. It relies on the coherent manipulation of atoms trapped in a magnetic double-well potential, for which the author developed a novel type of beam splitter. Particle-wave duality enables the construction of interferometers for matter waves, which complement optical interferometers in precision measurement devices, both for technological applications and fundamental tests. This requires the development of atom-optics analogues to beam splitters, phase shifters and recombiners. Particle interactions in the Bose-Einstein condensate lead to a nonlinearity, absent in photon optics. This is exploited to generate a non-classical state with reduced atom-number fluctuations inside the interferometer. This state is then used to study the interaction-induced dephasing of the quantum superposition. The resulting coherence times are found to be a factor of three longer than expected for coherent states, highlighting the potential of entanglement as a resource for quantum-enhanced metrology.

In this thesis, ultimate sensitive measurement for weak force imposed on a suspended mirror is performed with the help of a laser and an optical cavity for the development of gravitational-wave detectors. According to the Heisenberg uncertainty principle, such measurements are subject to a fundamental noise called quantum noise, which arises from the quantum nature of a probe (light) and a measured object (mirror). One of the sources of quantum noise is the quantum back-action, which arises from the vacuum fluctuation of the light. It sways the mirror via the momentum transferred to the mirror upon its reflection for the measurement. The author discusses a fundamental trade-off between sensitivity and stability in the macroscopic system, and suggests using a triangular cavity that can avoid this trade-off. The development of an optical triangular cavity is described and its characterization of the optomechanical effect in the triangular cavity is demonstrated. As a result, for the first time in the world the quantum back-action imposed on the 5-mg suspended mirror is significantly evaluated. This work contributes to overcoming the standard quantum limit in the future.

This thesis describes significant advances in experimental capabilities using ultracold polar molecules. While ultracold polar molecules are an idyllic platform for quantum chemistry and quantum many-body physics, molecular samples prior to this work failed to be quantum degenerate, were plagued by chemical reactions, and lacked any evidence of many-body physics. These limitations were overcome by loading molecules into an optical lattice to control and eliminate collisions and hence chemical reactions. This led to observations of many-body spin dynamics using rotational states as a pseudo-spin, and the realization of quantum magnetism with long-range interactions and strong many-body correlations. Further, a 'quantum synthesis' technique based on atomic insulators allowed the author to increase the filling fraction of the molecules in the lattice to 30%, a substantial advance which corresponds to an entropy-per-molecule entering the quantum degenerate regime and surpasses the so-called percolations threshold where long-range spin propagation is expected. Lastly, this work describes the design, construction, testing, and implementation of a novel apparatus for controlling polar molecules. It provides access to: high-resolution molecular detection and addressing; large, versatile static electric fields; and microwave-frequency electric fields for driving rotational transitions with arbitrary polarization. Further, the yield of molecules in this apparatus has been demonstrated to exceed 10^5, which is a substantial improvement beyond the prior apparatus, and an excellent starting condition for direct evaporative cooling to quantum degeneracy.

This book describes the life, times and science of the Soviet physicist Lev Vasilevich Shubnikov (1901-1937). From 1926 to 1930 Shubnikov worked in Leiden where he was the co-discoverer of the Shubnikov-De Haas effect. After his return to the Soviet Union he founded in Kharkov in Ukraine the first low-temperature laboratory in the Soviet Union, which in a very short time became the foremost physics institute in the country and among other things led to the discovery of type-II superconductivity. In August 1937 Shubnikov, together with many of his colleagues, was arrested and shot early in November 1937. This gripping story gives deep insights into the pioneering work of Soviet physicists before the Second World War, as well as providing much previously unpublished information about their brutal treatment at the hands of the Stalinist regime.

This thesis explores several fundamental topics in mesoscopic circuitries that incorporate few electronic conduction channels. It reports a series of long-awaited experiments that establish a new state of the art. The first experiments address the quantized character of charge in circuits. We demonstrate the charge quantization criterion, observe the predicted charge quantization scaling and a crossover toward a universal behavior as temperature is increased. The second set of experiments addresses the unconventional quantum critical physics that arises in the multichannel Kondo model. We observe the predicted universal Kondo fixed points and validate the numerical renormalization group scaling curves. Away from the quantum critical point, we obtain a direct visualization of the development of a second-order quantum phase transition.

The enlarged new edition of this textbook provides a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The novel fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a concise description of modern plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple and emphasizes the underlying concepts. The guidelines of plasma physics are illustrated by a host of practical examples, preferentially from plasma diagnostics. There, Langmuir probe methods, laser interferometry, ionospheric sounding, Faraday rotation, and diagnostics of dusty plasmas are discussed. Though primarily addressing students in plasma physics, the book is easily accessible for researchers in neighboring disciplines, such as space science, astrophysics, material science, applied physics, and electrical engineering. This second edition has been thoroughly revised and contains substantially enlarged chapters on plasma diagnostics, dusty plasmas and plasma discharges. Probe techniques have been rearranged into basic theory and a host of practical examples for probe techniques in dc, rf, and space plasmas. New topics in dusty plasmas, such as plasma crystals, Yukawa balls, phase transitions and attractive forces have been adopted. The chapter on plasma discharges now contains a new section on conventional and high-power impulse magnetron sputtering. The recently discovered electrical asymmetry effect in capacitive rf-discharges is described. The text is based on an introductory course to plasma physics and advanced courses in plasma diagnostics, dusty plasmas, and plasma waves, which the author has taught at Kiel University for three decades. The pedagogical approach combines detailed explanations, a large number of illustrative figures, short summaries of the basics at the end of each chapter, and a selection of problems with detailed solutions.

This thesis represents a decisive breakthrough in our understanding of the physics of universal quantum-mechanical three-body systems. The Efimov scenario is a prime example of how fundamental few-body physics features universally across seemingly disparate fields of modern quantum physics. Initially postulated for nuclear physics more than 40 years ago, the Efimov effect has now become a new research paradigm not only in ultracold atomic gases but also in molecular, biological and condensed matter systems. Despite a lot of effort since its first observations, the scaling behavior, which is a hallmark property and often referred to as the "holy grail" of Efimov physics, remained hidden until recently. In this work, the author demonstrates this behavior for the first time for a heteronuclear mixture of ultracold Li and Cs atoms, and pioneers the experimental understanding of microscopic, non-universal properties in such systems. Based on the application of Born-Oppenheimer approximation, well known from molecular physics textbooks, an exceptionally clear and intuitive picture of heteronuclear Efimov physics is revealed.

This book presents the basics and applications of superconducting magnets. It explains the phenomenon of superconductivity, theories of superconductivity, type II superconductors and high-temperature cuprate superconductors. The main focus of the book is on the application to superconducting magnets to accelerators and fusion reactors and other applications of superconducting magnets. The thermal and electromagnetic stability criteria of the conductors and the present status of the fabrication techniques for future magnet applications are addressed. The book is based on the long experience of the author in studying superconducting materials, building magnets and numerous lectures delivered to scholars. A researcher and graduate student will enjoy reading the book to learn various aspects of magnet applications of superconductivity. The book provides the knowledge in the field of applied superconductivity in a comprehensive way.

In this thesis, the author investigates hidden-order phase transition at T0 = 17.5 K in the heavy-fermion URu2Si2. The four-fold rotational symmetry breaking in the hidden order phase, which imposes a strong constraint on the theoretical model, is observed through the magnetic torque measurement. The translationally invariant phase with broken rotational symmetry is interpreted as meaning that the hidden-order phase is an electronic "nematic" phase. The observation of such nematicity in URu2Si2 indicates a ubiquitous nature among the strongly correlated electron systems. The author also studies the superconducting state of URu2Si2 below Tc = 1.4 K, which coexists with the hidden-order phase. A peculiar vortex penetration in the superconducting state is found, which may be related to the rotational symmetry breaking in the hidden-order phase. The author also identifies a vortex lattice melting transition. This transport study provides essential clues to the underlying issue of quasiparticle dynamics as to whether a quasiparticle Bloch state is realized in the periodic vortex lattice.