Author: Harry Suhl
Publisher: OUP Oxford
ISBN: 0191523674
Category : Science
Languages : en
Pages : 208
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Book Description
Electrons in solids behave like microscopic bar magnets, and in certain solids these align to produce macroscopic magnetizations. This book deals with the dynamics of this magnetization field. It addresses questions of microscopic mechanism only to the extent that residual interactions of the magnetic moments with other degrees of freedom of the host solid affect the dynamics, particularly the dissipative aspects. Several of these damping mechanisms are evaluated here for their effect on the equations of the magnetization dynamics. This dynamics is intrinsically nonlinear. This is important in the applications, particularly magnetic recording, which involves very large motion of the magnetization, well beyond the validity of linearized (small motion) approximations or limited extensions thereof. Therefore nonlinear solution methods are emphasized, but with only minimal use of numerical simulation. The book should be useful to practitioners of magnetic recording, and to physicists studying magnetic phenomena.
Author: William T Coffey
Publisher: World Scientific
ISBN: 9811217297
Category : Science
Languages : en
Pages : 709
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Book Description
Presenting in a coherent and accessible fashion current results in nanomagnetism, this book constitutes a comprehensive, rigorous and readable account, from first principles of the classical and quantum theories underlying the dynamics of magnetic nanoparticles subject to thermal fluctuations.Starting with the Larmor-like equation for a giant spin, both the stochastic (Langevin) equation of motion of the magnetization and the associated evolution (Fokker-Planck) equation for the distribution function of the magnetization orientations of ferromagnetic nanoparticles (classical spins) in a heat bath are developed along with their solution (using angular momentum theory) for arbitrary magnetocrystalline-Zeeman energy. Thus, observables such as the magnetization reversal time, relaxation functions, dynamic susceptibilities, etc. are calculated and compared with the predictions of classical escape rate theory including in the most general case spin-torque-transfer. Regarding quantum effects, which are based on the reduced spin density matrix evolution equation in Hilbert space as is described at length, they are comprehensively treated via the Wigner-Stratonovich formulation of the quantum mechanics of spins via their orientational quasi-probability distributions on a classically meaningful representation space. Here, as suggested by the relevant Weyl symbols, the latter is the configuration space of the polar angles. Hence, one is led, by mapping the reduced density matrix equation onto that space, to a master equation for the quasi-probability evolution akin to the Fokker-Planck equation which may be solved in a similar way. Thus, one may study in a classical-like manner the evolution of observables with spin number ranging from an elementary spin to molecular clusters to the classical limit, viz. a nanoparticle. The entire discussion hinges on the one-to-one correspondence between polarization operators in Hilbert space and the spherical harmonics allied to concepts of spin coherent states long familiar in quantum optics.Catering for the reader with only a passing knowledge of statistical and quantum mechanics, the book serves as an introductory text on a complicated subject where the literature is remarkably sparse.
Author: Timothy R. Field
Publisher: International Monographs on Ph
ISBN: 0198570775
Category : Business & Economics
Languages : en
Pages : 199
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Book Description
The book develops the dynamical theory of scattering from random media from first principles. Its key findings are to characterize the time evolution of the scattered field in terms of stochastic differential equations, and to illustrate this framework in simulation and experimental data analysis. The physical models contain all correlation information and higher order statistics, which enables radar and laser scattering experiments to be interpreted. An emphasis is placed on the statistical character of the instantaneous fluctuations, as opposed to ensemble average properties. This leads to various means for detection, which have important consequences in radar signal processing and statistical optics. The book is also significant also because it illustrates how ideas in mathematical finance can be applied to physics problems in which non-Gaussian noise processes play an essential role. This pioneering book represents a significant advance in this field, and should prove valuable to leading edge researchers and practitioners at the postgraduate level and above.
Author: Marcos Marino
Publisher: Oxford University Press
ISBN: 0191524530
Category : Science
Languages : en
Pages : 210
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Book Description
In recent years, the old idea that gauge theories and string theories are equivalent has been implemented and developed in various ways, and there are by now various models where the string theory / gauge theory correspondence is at work. One of the most important examples of this correspondence relates Chern-Simons theory, a topological gauge theory in three dimensions which describes knot and three-manifold invariants, to topological string theory, which is deeply related to Gromov-Witten invariants. This has led to some surprising relations between three-manifold geometry and enumerative geometry. This book gives the first coherent presentation of this and other related topics. After an introduction to matrix models and Chern-Simons theory, the book describes in detail the topological string theories that correspond to these gauge theories and develops the mathematical implications of this duality for the enumerative geometry of Calabi-Yau manifolds and knot theory. It is written in a pedagogical style and will be useful reading for graduate students and researchers in both mathematics and physics willing to learn about these developments.
Author: Armando Francesco Borghesani
Publisher: OUP Oxford
ISBN: 0191526711
Category : Science
Languages : en
Pages : 559
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Book Description
Electrons and ions have been used for over 40 years as probes to investigate the fascinating properties of helium liquids. The study of the transport properties of microscopic charge carriers sheds light on superfluidity, on quantum hydrodynamics, and on the interactions with collective excitations in quantum liquids. The structure of the probes themselves depends on their coupling with the liquid environment in a way that gives further insight into the microscopic behavior of the liquid in different thermodynamic conditions, such as in the superfluid phase, in the normal phase, or near the liquid-vapor critical point. This book provides a comprehensive review of the experiments and theories of transport properties of charge carriers in liquid helium. It is a subject about which no other monograph exists to date. The book is intended for graduate and postgraduate students and for condensed matter physicists who will benefit from its completeness and accuracy.
Author: Vladimir Fortov
Publisher: Oxford University Press
ISBN: 0199299803
Category : Science
Languages : en
Pages : 535
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Book Description
The book is devoted to the physics of plasma at high density, which has been compressed so strongly that the effects of interparticle interactions and non-ideality govern its behavior. Interest in this non-traditional plasma has been generated in recent years when states of matter with high concentration of energy became accessible experimentally as the basis of modern technologies and facilities. The greatest part of the matter in the Universe is in this exotic state. In this book,the methods of generation and diagnostics of strongly coupled plasmas are presented, along with the main theoretical methods and experimental results on thermodynamical, kinetic and optical properties. Particular attention is given to fast developing modern directions of strongly coupled plasmaphysics such as metallization of dielectrics and dielectrization of metals, non-neutral plasmas, dusty plasmas and their crystallization. The book is written for physicists and astrophysicists, engineers, and material scientists.
Author: Stuart A. Rice
Publisher: John Wiley & Sons
ISBN: 1119290945
Category : Science
Languages : en
Pages : 574
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Book Description
The Advances in Chemical Physics series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. • This is the only series of volumes available that presents the cutting edge of research in chemical physics. • Includes contributions from experts in this field of research. • Contains a representative cross-section of research that questions established thinking on chemical solutions • Structured with an editorial framework that makes the book an excellent supplement to an advanced graduate class in physical chemistry or chemical physics
Author: Franco Strocchi
Publisher: OUP Oxford
ISBN: 0191651346
Category : Science
Languages : en
Pages : 608
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Book Description
Quantum Field Theory (QFT) has proved to be the most useful strategy for the description of elementary particle interactions and as such is regarded as a fundamental part of modern theoretical physics. In most presentations, the emphasis is on the effectiveness of the theory in producing experimentally testable predictions, which at present essentially means Perturbative QFT. However, after more than fifty years of QFT, we still are in the embarrassing situation of not knowing a single non-trivial (even non-realistic) model of QFT in 3+1 dimensions, allowing a non-perturbative control. As a reaction to these consistency problems one may take the position that they are related to our ignorance of the physics of small distances and that QFT is only an effective theory, so that radically new ideas are needed for a consistent quantum theory of relativistic interactions (in 3+1 dimensions). The book starts by discussing the conflict between locality or hyperbolicity and positivity of the energy for relativistic wave equations, which marks the origin of quantum field theory, and the mathematical problems of the perturbative expansion (canonical quantization, interaction picture, non-Fock representation, asymptotic convergence of the series etc.). The general physical principles of positivity of the energy, Poincare' covariance and locality provide a substitute for canonical quantization, qualify the non-perturbative foundation and lead to very relevant results, like the Spin-statistics theorem, TCP symmetry, a substitute for canonical quantization, non-canonical behaviour, the euclidean formulation at the basis of the functional integral approach, the non-perturbative definition of the S-matrix (LSZ, Haag-Ruelle-Buchholz theory). A characteristic feature of gauge field theories is Gauss' law constraint. It is responsible for the conflict between locality of the charged fields and positivity, it yields the superselection of the (unbroken) gauge charges, provides a non-perturbative explanation of the Higgs mechanism in the local gauges, implies the infraparticle structure of the charged particles in QED and the breaking of the Lorentz group in the charged sectors. A non-perturbative proof of the Higgs mechanism is discussed in the Coulomb gauge: the vector bosons corresponding to the broken generators are massive and their two point function dominates the Goldstone spectrum, thus excluding the occurrence of massless Goldstone bosons. The solution of the U(1) problem in QCD, the theta vacuum structure and the inevitable breaking of the chiral symmetry in each theta sector are derived solely from the topology of the gauge group, without relying on the semiclassical instanton approximation.
Author: Ilias Vardavas
Publisher: International Monographs on Ph
ISBN: 0199697140
Category : Nature
Languages : en
Pages : 512
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Book Description
This new book describes the basic physics of solar and infrared radiation in the atmosphere. Radiation theory is related to the development of climate prediction models, and to measurement techniques for monitoring the Earth's energy budget and making remote sensing observations from satellites.
Author: Walter T. Grandy, Jr.
Publisher: Oxford University Press on Demand
ISBN: 0199546177
Category : Language Arts & Disciplines
Languages : en
Pages : 224
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Book Description
The book explicates the concept of entropy, particularly its governance of all of thermal physics, over a broad range of equilibrium and nonequilibrium phenomena. Historical development and modern research are presented in the context of entropy as a fundamental element of probability theory and its relation to the notion of information.
