Dynamics of a Quantum Spin Liquid


Book Description

This thesis presents an exact theoretical study of dynamical correlation functions in different phases of a two-dimensional quantum spin liquid. By calculating the dynamical spin structure factor and the Raman scattering cross section, this thesis shows that there are salient signatures—qualitative and quantitative—of the Majorana fermions and the gauge fluxes emerging as effective degrees of freedom in the exactly solvable Kitaev honeycomb lattice model. The model is a representative of a class of spin liquids with Majorana fermions coupled to Z2 gauge fields. The qualitative features of the response functions should therefore be characteristic for this broad class of topological states.










Spin Dynamics


Book Description

Spin Dynamics: Basics of Nuclear Magnetic Resonance, Second Edition is a comprehensive and modern introduction which focuses on those essential principles and concepts needed for a thorough understanding of the subject, rather than the practical aspects. The quantum theory of nuclear magnets is presented within a strong physical framework, supported by figures. The book assumes only a basic knowledge of complex numbers and matrices, and provides the reader with numerous worked examples and exercises to encourage understanding. With the explicit aim of carefully developing the subject from the beginning, the text starts with coverage of quarks and nucleons and progresses through to a detailed explanation of several important NMR experiments, including NMR imaging, COSY, NOESY and TROSY. Completely revised and updated, the Second Edition features new material on the properties and distributions of isotopes, chemical shift anisotropy and quadrupolar interactions, Pake patterns, spin echoes, slice selection in NMR imaging, and a complete new chapter on the NMR spectroscopy of quadrupolar nuclei. New appendices have been included on Euler angles, and coherence selection by field gradients. As in the first edition, all material is heavily supported by graphics, much of which is new to this edition. Written for undergraduates and postgraduate students taking a first course in NMR spectroscopy and for those needing an up-to-date account of the subject, this multi-disciplinary book will appeal to chemical, physical, material, life, medical, earth and environmental scientists. The detailed physical insights will also make the book of interest for experienced spectroscopists and NMR researchers. • An accessible and carefully written introduction, designed to help students to fully understand this complex and dynamic subject • Takes a multi-disciplinary approach, focusing on basic principles and concepts rather than the more practical aspects • Presents a strong pedagogical approach throughout, with emphasis placed on individual spins to aid understanding • Includes numerous worked examples, problems, further reading and additional notes Praise from the reviews of the First Edition: "This is an excellent book... that many teachers of NMR spectroscopy will cherish... It deserves to be a ‘classic’ among NMR spectroscopy texts." NMR IN BIOMEDICINE "I strongly recommend this book to everyone…it is probably the best modern comprehensive description of the subject." ANGEWANDTE CHEMIE, INTERNATIONAL EDITION




Quantum Theory of the Electron Liquid


Book Description

Modern electronic devices and novel materials often derive their extraordinary properties from the intriguing, complex behavior of large numbers of electrons forming what is known as an electron liquid. This book provides an in-depth introduction to the physics of the interacting electron liquid in a broad variety of systems, including metals, semiconductors, artificial nano-structures, atoms and molecules. One, two and three dimensional systems are treated separately and in parallel. Different phases of the electron liquid, from the Landau Fermi liquid to the Wigner crystal, from the Luttinger liquid to the quantum Hall liquid are extensively discussed. Both static and time-dependent density functional theory are presented in detail. Although the emphasis is on the development of the basic physical ideas and on a critical discussion of the most useful approximations, the formal derivation of the results is highly detailed and based on the simplest, most direct methods.










Spin Dynamics of Li Doped La[sub 2]CuO[sub 4]with a Disordered Ground State


Book Description

Only 3% hole doping by Li is sufficient to suppress the long-range antiferromagnetic order in LazCu04. Spin dynamics in the disordered state was investigated by measuring the dynamic magnetic structure factor, S(q, w), as a function of temperature, using cold neutron spectroscopy, on La2Cuo. 96Lio.0404a nd La(almost equal to)Cuo.gLio. 104s ingle crystals. The details of observed spin dynamics of the quantum disordered spin liquid were compared to the theoretical results of the nonlinear u model for a two dimensional Heisenberg antiferromagnet, which predicts a phase crossover upon cooling from a quantum critical regime of a quantum spin liquid to its quantum paramagnetic regime.




Spin Ice


Book Description

This book deals with a new class of magnetic materials, spin ice. Spin ice has become the canonical example of modern frustrated magnetism where competing interactions between spins set the rules for an emergent magnetostatic gauge field theory. Excitations take the form of magnetic monopoles or can condense via a Higgs mechanism. Beyond classical spin ice, the book describes the new physics emerging when quantum coherence (spin liquids, photon-like excitations) and itinerant electrons (anomalous Hall effect) are included in artificial systems. This first book dedicated to spin ice is a review of the current understanding of the field, both on the theoretical and experimental levels, written by leading experts. The book is written in a linear way with very few prerequisites. It also contains textbook-like descriptions of theoretical methods to help advanced students and researchers to enter the field.