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Books > Science & Mathematics > Physics > Nuclear structure physics
The investigation ofmost problems of quantum physics leads to the solution of the Schrodinger equation with an appropriate interaction Hamiltonian or potential. However, the exact solutions are known for rather a restricted set of potentials, so that the standard eternal problem that faces us is to find the best effective approximation to the exact solution of the Schrodinger equation under consideration. In the most general form, this problem can be formulated as follows. Let a total Hamiltonian H describing a relativistic (quantum field theory) or a nonrelativistic (quantum mechanics) system be given. Our problem is to solve the Schrodinger equation Hlft = Enlftn, n i. e., to find the energy spectrum {En} and the proper wave functions {lft } n including the'ground state or vacuum lft = 10). The main idea of any ap o proximation technique is to find a decomposition in such a way that Ha describes our physical system in the "closest to H" manner, and the Schrodinger equation HolJt. (O) = E(O)lJt. (O) n n n can be solved exactly. The interaction Hamiltonian HI is supposed to give small corrections to the zero approximation which can be calculated. In this book, we shall consider the problem of a strong coupling regime in quantum field theory, calculations ofpath or functional integrals over the Gaussian measure and spectral problems in quantum mechanics. Let us con sider these problems briefly."
In the last twenty years polarized beams of slow neutrons have been used effectively in fundamental research in nuclear physics. Parity violation in nuclear fission and neutron optics was discoverd as well as the nuclear precession of neutrons and the coherent interference of spin channels in neutron capture by nuclei. Furthermore, these methods helped to understand better the neutron`s electric dipole moment and its beta decay. This book gives a thorough introduction to these experimental methods including the most recent techniques of generating and analyzing polarized neutral beams. It clearly shows the close relationship between elementary particle physics and nuclear physics, in particular in the section dealing with the effects caused by weak interactions. Special attention is paid to experiments which investigate the violation of quantum mechanical conservation laws. The book not only addresses specialists but also those interested in the foundations of elementary particle and nuclear physics. It is well suited as additional reading for students.
2. High Temperature UHV-STM System 264 3. Hydrogen Desorption Process on Si (111) Surface 264 4. (7x7) - (1 xl) Phase Transition on Si (111) Surface 271 Step Shifting under dc Electric Fields 275 5. 6. Conclusions 280 Acknowledgements and References 281 12. DYNAMIC OBSERVATION OF VORTICES IN SUPERCONDUCTORS USING ELECTRON WAVES 283 by Akira Tonomura 1. Introduction 283 2. Experimental Method 284 2. 1 Interference Microscopy 284 2. 2 Lorentz Microscopy 287 Observation of Superconducting Vortices 288 3. 3. 1 Superconducting Vortices Observed by Interference Microscopy 288 3. 1. 1 Profile Mode 288 3. 1. 2 Transmission Mode 291 3. 2 Superconducting Vortices Observed by Lorentz Microscopy 293 3. 3 Observation of Vortex Interaction with Pinning Centers 294 3. 3. 1 Surface Steps 295 3. 3. 2 Irradiated Point Defects 296 4. Conclusion 298 References 299 13. TEM STUDIES OF SOME STRUCTURALLY FLEXIBLE SOLIDS AND THEIR ASSOCIATED PHASE TRANSFORMATIONS 301 by Ray L. Withers and John G. Thompson 1. Introduction 301 2. Tetrahedrally Comer-Connected Framework Structures 302 3. Tetragonal a-PbO 311 4. Compositionally Flexible Anion-Deficient Fluorites and the "Defect Fluorite" to C-type Sesquioxide Transition 320 5. Summary and Conclusions 327 Acknowledgements and References 327 Author Index 331 Subject Index 333 List of Contributors A. ASEEV Institute of Semiconductor Physics, Russian Academy of Sciences Novosibirsk, 630090, pr. ac. , Lavrentjeva 13, RUSSIA E. BAUER Department of Physics and Astronomy, Arizona State University Tempe, AZ 85287-1504, U. S. A. G. H.
243 number n and orbital angular momentum 1, but also a total angular momentum 1 f = 1 +/- !. This modification lead to striking successes for the model. Almost without exception, the ground state spins of odd nuclei were found to be cor rectly predicted. Furthermore several other features of nuclei such as the occur rence of isomeric states and the values of magnetic dipole moments were explained, at least qualitatively. However the model completely failed to explain the large values of observed electric quadrupole moments and certain regularities in nuclear spectra, especially of rare earth nuclei. 4. 1950-1953. The emphatic success of the shell-model modified by a spin orbit force gave the necessary confidence and incentive to physicists to apply the model in detail to individual nuclei. Guided by parallel calculations in atomic spectroscopy, considerable effort was devoted to computing spectra of levels of nuclear systems with the so-called "Intermediate Coupling Model" in which the independent particle motion is considered to be perturbed by central particle particle interactions and spin-orbit forces. Computational labour restricts such calculations to nuclei near closed shells, say within four particles or holes of closed shells. This explains why only light nuclei (A < 20) and isolated groups of nuclei higher in the Periodic Table were thus treated. Usually such calculations were rewarded by agreement with experiment especially those for light nuclei 2 and 20S nuclei near the double closed shell at Pb 3.
The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking-the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. It documents one of the flagship measurements of the D0 experiment, a collaboration of more than 600 physicists from around the world. It describes first observation of a physical process known as "single top quark production", which had been sought for more than 10 years before its eventual discovery in 2009. Further, his thesis describes, in detail, the innovative approach Dr. Gillberg took to this analysis. Through the use of Boosted Decision Trees, a machine-learning technique, he observed the tiny single top signal within an otherwise overwhelming background. This Doctoral Thesis has been accepted by Simon Fraser University, Burnaby, BC, Canada.
ThisvolumeisacollectionofarticlesoriginallypublishedonaSpecialIssueoftheAstrophysicsandSpaceScienceJournal. It is intended to give a comprehensive overview of the current state of knowledge in solar and stellar modelling, with the aim of comparing and extending what we know from the detailed solar modelling, made possible by the helioseismic tools and by the recent analysis of the solar spectrum, to the modelling and understanding of generic stellar structures and their evolution. Particular emphasis is devoted to the role of the input physics, and its relevant uncertainties, in the construction of stellar models and in the resulting predictions for general observable quantities. Issues related to convection, overshoot, diffusion and settling of helium and heavy elements, rotation, chemical composition and magnetic eld are extensively discussed. Large space is dedicated to the application of helio- and asteroseismic techniques as tools to prove the theory of the evolution and the structure of the stars. Comments on prospects for future improvements and re nements of the theoretical models are given, focusing on the possibility of getting ever more precise helioseismic and asteroseismic observations from ground and space. The articles included in this volume are the results of the HELAS-NA5 workshop 'Synergies between solar and stellar modelling' held in Rome from 22nd to 26th of June 2009, which was an unique occasion to gather the solar and the stellar physics communities to discuss the urgent questions risen by recent photometric and spectroscopic observational results.
Infrared spectroscopy is a new and innovative technology to study protein folding/misfolding events in the broad arsenal of techniques conventionally used in this field. The progress in understanding protein folding and misfolding is primarily due to the development of biophysical methods which permit to probe conformational changes with high kinetic and structural resolution. The most commonly used approaches rely on rapid mixing methods to initiate the folding event via a sudden change in solvent conditions. Traditionally, techniques such as fluorescence, circular dichroism or visible absorption are applied to probe the process. In contrast to these techniques, infrared spectroscopy came into play only very recently, and the progress made in this field up to date which now permits to probe folding events over the time scale from picoseconds to minutes has not yet been discussed in a book. The aim of this book is to provide an overview of the developments as seen by some of the main contributors to the field. The chapters are not intended to give exhaustive reviews of the literature but, instead to illustrate examples demonstrating the sort of information, which infrared techniques can provide and how this information can be extracted from the experimental data. By discussing the strengths and limitations of the infrared approaches for the investigation of folding and misfolding mechanisms this book helps the reader to evaluate whether a particular system is appropriate for studies by infrared spectroscopy and which specific advantages the techniques offer to solve specific problems.
These lectures review the recently developed vector coherent state method. The book is an excellent introduction to the field because of the many examples treated in detail, in particular those from nuclear and particle physics. These calculations will be welcomed by researchers and graduate students. The author reviews the concepts of coherent states of the Heisenberg algebra and shows then that the vector coherent state method maps the higher symmetry algebra into an n-dimensional harmonic oscillator algebra coupled with a simple intrinsic symmetry algebra. The formulation involves some vector (or analogous higher symmetry) coupling of the intrinsic algebra with the n-dimensional oscillator algebra, leading to matrix representations and Wigner coefficients of the higher symmetry algebra expressed in terms of simple calculable functions and recoupling coefficients for the simpler intrinsic algebra.
The recent discovery of a type II supernova in the Large Magellanic Cloud provides a rare chance to compare models of stellar evolution and nucleosynthesis directly with observations. This workshop covers thermonuclear reaction rates in chaos (experimental and theoretical), stellar evolution, nucleosynthesis and isotopic anomalies in meteorites and, in a final section, the supernovae, in particular SN 1987A. It brings the most interesting news in the rapidly developing field of nuclear astrophysics to researchers and also to graduate students. Recent and future developments are discussed. Special emphasis is placed on experimental and theoretical approaches to obtaining nuclear reaction rates, models of stellar evolution and explosions, and theories of nucleosynthesis. Various aspects of stellar evolution, nucleosynthesis, and thermonuclear reactions of astrophysical interest are reviewed. Several contributions deal with supernova explosions of massive stars, and in particular with Supernova 1987A and its impact on current models of the evolution of massive stars, the gravitational collapse of stellar cores, and neutrino physics and astronomy.
Frontiers in Fusion Research provides a systematic overview of the latest physical principles of fusion and plasma confinement. It is primarily devoted to the principle of magnetic plasma confinement, that has been systematized through 50 years of fusion research. Frontiers in Fusion Research begins with an introduction to the study of plasma, discussing the astronomical birth of hydrogen energy and the beginnings of human attempts to harness the Sun's energy for use on Earth. It moves on to chapters that cover a variety of topics such as: * charged particle motion, * plasma kinetic theory, * wave dynamics, * force equilibrium, and * plasma turbulence. The final part of the book describes the characteristics of fusion as a source of energy and examines the current status of this particular field of research. Anyone with a grasp of basic quantum and analytical mechanics, especially physicists and researchers from a range of different backgrounds, may find Frontiers in Fusion Research an interesting and informative guide to the physics of magnetic confinement.
The fifteenth European Conference on Few-Body Problems in Physics has taken place during the week of June 5th to 9th, in the lovely village of Peniscola, approximately midway between Barcelona and Valencia on the Mediterranean coast. This conference continues the tradition initiated in 1972 at Budapest, where the first conference took place, and followed in Graz (1973), Tiibingen (1975), Vlieland (1976), Uppsala (1977), Dubna (1979), Sesimbra (1980), Fer- rara (1981), Tbilisi (1984), Fontevraud (1987), Uzhgorod (1990), Elba (1991) and Amsterdam (1993). During this week, a total of one hundred and fifty one scientist were exchang- ing their knowledge and initiatives in this broad field of Few-Body Physics. Even if the name of the conference restricts its domain to Europe, there has been an important participation of scientists from non-European countries. A conference with more than twenty years of tradition is already an au- tonomous being, with a noticeable inertia. Nevertheless, it is a reasonable thought to bend this inertia trying to introduce some innovation, of course, without any damage to the basic structure and objectives of the conference.
In this volume seven leading theoreticians and experimenters review the origin of the asymmetry of matter and antimatter in the Big Bang, solar neutrinos, the physics of enormous densities and temperatures in stars and of immense magnetic fields around collapsed stars, strong electric fields in heavy ion collisions, and the extreme conditions in quark-gluon plasmas. The articles address nuclear and particle physicists, especially graduate students, but also astrophysicists and cosmologists, since they have to deal with events under the extreme physical conditions discussed here.
In the present edition, a number of new features have been added. First of all, a number of typographical errors that had crept into the text have been corrected. More importantly, a number of new examples, figures and smaller sections have been added. In evaluating the two-body matrix elements which characterize the residual interaction, attention has been paid to the multipole expansion and insight into the importance of various multipoles is presented. The 18 example of 0 is now worked out for all the different angular momentum states in the section on configuration mixing. Some additional comments on how to determine one- and two-body matrix elements in jn configurations, on isospin and the application of isospin to the study of light odd-odd nuclei are included. In Chap. 3, a small section on the present use of large-scale shell model calculations and a section on experimental tests of how a nucleon actually moves inside the nucleus (using electromagnetic probing of nucleonic motion) has been added. In Chap. 4, some recent applications of the study of quadrupole motion in jn particle systems (with reference to the Po, Rn, Ra nuclei) are presented. In the discussion of magnetic dipole moments, the effects and importance of collective admixtures are pointed out and discussed. In Chap. 5, some small additions relating to the particle-hole conjugation and to the basic Hartree-Fock theory have been made. In Chap.
Charge density analysis of materials provides a firm basis for the evaluation of the properties of materials. The design and engineering of a new combination of metals requires a firm knowledge of intermolecular features. Recent advances in technology and high-speed computation have made the crystal X-ray diffraction technique a unique tool for the determination of charge density distribution in molecular crystal. Methods have been developed to make experimental probes capable of unraveling the features of charge densities in the intra- and inter-molecular regions of crystal structures. In Metal and Alloy Bonding - An Experimental Analysis, the structural details of materials are elucidated with the X-ray diffraction technique. Analyses of the charge density and the local and average structure are given to reveal the structural properties of technologically important materials. Readers will gain a new understanding of the local and average structure of existing materials. The electron density, bonding, and charge transfer studies in Metal and Alloy Bonding - An Experimental Analysis contain useful information for researchers in the fields of physics, chemistry, materials science, and metallurgy. The properties described in these studies can contribute to the successful engineering of these technologically important materials.
Scattering theory is of interest to physicists and to chemists and has a wide variety of applications, but it also presents a considerable challenge to mathematicians, including numerical analysts. Within the Schroedinger picture in this volume are collected the various theoretical and mathematical treatments of scattering together with a host of reviews of its applications to atomic and nuclear physics, to surface physics and chemistry, for example trapping of atoms on surfaces, and to amorphous condensed systems. The reviews give a concise and pedagogically useful presentation of the state of the art, and may serve as introductions for newcomers, in particular for graduate students.
This book begins with a very readable survey "The Sun Today" by J.-C. Pecker. It is followed by thorough reviews from leading experts covering theory and observations. The focus shifts from the solar core, studied via neutrino emissions and helioseismology, through the interface regions where it is believed the large-scale magnetic fields are generated, to the corona, where most of the high temperature phenomena characteristic of this region may be studied directly. As energetic particles play such a vigorous role in this part of the sun, a separate session was devoted to their transport and storage in the corona.
Measuring the hydrogen content in materials is important both for research and for various applications in material and surface sciences, such as hydrogen embrittlement of steel, controlled thermonuclear reaction first wall studies, and changed material properties caused by dissolved hydrogen. Hydrogen is the most difficult atomic species to analyze by traditional methods, but nuclear physics methods are particularly suited for this purpose. President of the Uzbek SSR Academy of Sciences P.K. Khabibullaev and Professor B.G. Skorodumov discuss in this book the characteristics of these methods, such as lower detection limits, selectivity in respect to different isotopes, accuracy, depth resolution and maximum detection depth. Examples of applications that are dealt with include the determination of material humidity, the dating of objects, the study of hydrogen diffusion including non-stationary processes, and the investigation of changes in material properties like superconductivity, plasticity and electrical properties due to contamination by hydrogen.
Studying the interactions between heavy hydrogen isotopes and hydride forming metals or intermetallic compounds (IMC) is of importance for both fundamental and applied sciences. These systems offer, for example, the possibility of technical hydrogen isotope separation due to their considerable isotope effects. In addition, quite a lot of problems of hydrogen recovery, hydrogen purification, and tritium storage can be solved. This review deals with theoretical aspects of the interaction of heavy hydrogen isotopes with metals and IMC, and contains detailed information on phase and isotopic equilibrium and of the kinetics of isotope exchange in systems with hydride phases. Numerical data and results from theoretical and experimental studies are presented as well. |
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