Showing papers in "Reviews of Modern Physics in 1977"
TL;DR: The renormalization group theory has been applied to a variety of dynamic critical phenomena, such as the phase separation of a symmetric binary fluid as mentioned in this paper, and it has been shown that it can explain available experimental data at the critical point of pure fluids, and binary mixtures, and at many magnetic phase transitions.
Abstract: An introductory review of the central ideas in the modern theory of dynamic critical phenomena is followed by a more detailed account of recent developments in the field. The concepts of the conventional theory, mode-coupling, scaling, universality, and the renormalization group are introduced and are illustrated in the context of a simple example---the phase separation of a symmetric binary fluid. The renormalization group is then developed in some detail, and applied to a variety of systems. The main dynamic universality classes are identified and characterized. It is found that the mode-coupling and renormalization group theories successfully explain available experimental data at the critical point of pure fluids, and binary mixtures, and at many magnetic phase transitions, but that a number of discrepancies exist with data at the superfluid transition of $^{4}\mathrm{He}$.
4,980 citations
TL;DR: In this paper, the measurements of the hyperfine structure of free, naturally occurring, alkali atoms are reviewed and the experimental methods are discussed, as well as the relationships between hyperfine data and other atomic constants.
Abstract: The measurements of the hyperfine structure of free, naturally occurring, alkali atoms are reviewed. The experimental methods are discussed, as are the relationships between hyperfine structure data and other atomic constants.
749 citations
554 citations
TL;DR: In this article, the authors discuss how solutions to field equations, treated as classical, c-number nonlinear differential equations, expose unexpected states in the quantal Hilbert space with novel quantum numbers which arise from topological properties of the classical field configuration or from the mixing of internal and space-time symmetries.
Abstract: Recent researches have shown that it is possible to obtain information about the physical content of nontrivial quantum field theories by semiclassical methods. This article reviews some of these investigations. We discuss how solutions to field equations, treated as classical, c-number nonlinear differential equations, expose unexpected states in the quantal Hilbert space with novel quantum numbers which arise from topological properties of the classical field configuration or from the mixing of internal and space-time symmetries. Also imaginary-time, c-number solutions are reviewed. It is shown that they provide nonperturbative information about the vacuum sector of the quantum theory.
547 citations
TL;DR: In this paper, a number of apparently disparate problems from engineering, meteorology, geophysics, fluid mechanics and applied mathematics are considered under the unifying heading of natural convection.
Abstract: A number of apparently disparate problems from engineering, meteorology, geophysics, fluid mechanics and applied mathematics are considered under the unifying heading of natural convection. After a review of the mathematical framework that serves to delineate these problems, the heuristic approach to Benard and Rayleigh convection is discussed with special attention to buoyancy and surface tension. Then consideration is given to some aspects of scaling, and the nondimensionalization of equations to a given problem. The thermohydrodynamic description of a Newtonian fluid is presented, and the Boussinesq--Oberbeck model. This is followed by a treatment of the linear stability problem, and a description of the basic ideas of Landau and Hopf concerning the bifurcation of secondary solutions. Quantitative, though approximate, estimations are given for quantities belonging to the nonlinear steady convective regime: flow velocity and temperature distribution. Higher-order, though steady, bifurcations are discussed, as well as the transition to turbulence, along with such time-dependent phenomena as relaxation oscillations. The paper concludes with an Appendix showing a simple application of the Leray--Schauder topological degree of a mapping.
524 citations
TL;DR: Theories of the mechanics, thermodynamics, kinetics, and shear strength of shock-loaded materials are described and experimental techniques are briefly reviewed in this paper, and comprehensive tabulations of experimental observations are presented and materials that have been subjected to in-depth study are reviewed in more detail.
Abstract: First-order polymorphic, second-order, melting, and freezing transitions induced by shock-wave loading are reviewed. Comprehensive tabulations of the experimental observations are presented and materials that have been subjected to in-depth study are reviewed in more detail. Theories of the mechanics, thermodynamics, kinetics, and shear strength of shock-loaded materials are described and experimental techniques are briefly reviewed.
518 citations
TL;DR: The theory of nuclear electron capture is reviewed in the light of current understanding of weak interactions in this article, and experimental methods and results regarding capture probabilities, capture ratios, and EC/Beta(+) ratios are summarized.
Abstract: The theory of nuclear electron capture is reviewed in the light of current understanding of weak interactions. Experimental methods and results regarding capture probabilities, capture ratios, and EC/Beta(+) ratios are summarized. Radiative electron capture is discussed, including both theory and experiment. Atomic wave function overlap and electron exchange effects are covered, as are atomic transitions that accompany nuclear electron capture. Tables are provided to assist the reader in determining quantities of interest for specific cases.
304 citations
TL;DR: In this paper, the authors give a partial argument for the simultaneous existence of asymptotic freedom and trapping O/sub 2/ in the quark-string case in statistical mechanics.
Abstract: Recent work by K.G.Wilson, A.A.Migdal and others has led to a statistical mechanical treatment of systems of interaction quarks and strings. This work is summarized here. The major topics discussed include boson and fermion variables in statistical mechanics; descriptions of local and gauge symmetries; exact solutions of one-dimensional problems with nearest-neighbor interactions; exact solutions of two dimensional problems with plaquette interactions; Wilson's model of quarks and strings; asymptotic freedom and trapping for this model; the effect of a phase transition in this system; approximate recursion relations of the Migdal form. Finally, all this is put together to give a partial argument for the simultaneous existence of asymptotic freedom and trapping O/sub 2/ in the quark-string case. Arguments are developed which distinguish this case from the superficially analogous example of quantum electrodynamics.
182 citations
TL;DR: In this article, the authors discuss the time-independent perturbation formalism of Brandow for effective interactions and operators in a nonrigorous, intuitive way, and provide numerical calculations of the effective interaction and the effective charge.
Abstract: In this tutorial-style article we discuss the time-independent perturbation formalism of Brandow for effective interactions and operators in a nonrigorous, intuitive way. The simple example of a 2\ifmmode\times\else\texttimes\fi{}2 matrix is used to introduce the basic concepts, for instance the notion of folded diagrams. The same example is used subsequently in a discussion of the branch points arising from "level crossings" and the associated convergence difficulties with the perturbation series. Numerical calculations of the effective interaction and the effective charge are then reviewed, focussing, for the most part, on the ($1s0d$) shell. Whenever possible, simple physical models are used to illustrate the results. A fairly comprehensive summary of the calculations to date is given, and we attempt to synthesize and draw conclusions.
145 citations
TL;DR: In this article, a deformed singleparticle potential mode with residual interactions was applied to an analysis of states in odd-mass nuclides with $Ag228$, and configuration assignments were presented for many levels.
Abstract: A deformed single-particle potential mode, with residual interactions, is applied to an analysis of states in odd-mass nuclides with $Ag228$, and configuration assignments are presented for many levels. The systematics of energy level spacings throughout the actinides are studied, and the values of the nuclear deformation parameters that are appropriate to these nuclides are discussed. Tables of occupation probabilities and single-particle matrix elements are provided to facilitate the comparison of future measurements with theoretical expectations.
144 citations
TL;DR: In this article, the principles of interaction of energetic electrons with atoms are reviewed with emphasis on effects due to the crystalline structure of the target, and the available experimental results on defect production and recovery in metal crystals are reviewed in detail, and basic information, such as threshold energies for displacement in the main crystallographic directions and electrical resistivities of Frenkel pairs, are extracted.
Abstract: The principles of interaction of energetic electrons with atoms are reviewed with emphasis on effects due to the crystalline structure of the target. Computer "experiments" and analytic models that simulate the collision processes in a crystalline lattice are described and analyzed. The experimental part discusses, first, the techniques used for the investigation of point defects in single crystals. Then, the available experimental results on defect production and recovery in metal crystals are reviewed in detail, and basic information, such as threshold energies for displacement in the main crystallographic directions and electrical resistivities of Frenkel pairs, is extracted. Finally, it is shown how interatomic potentials can be deduced from the experimental results.
TL;DR: In this article, a short review of recent experimental and theoretical studies of phonon interactions in superfluid helium is presented, where the authors discuss the influence of this special property of phonons collisions on the hydrodynamics of the phonon gas, and consider the solutions of the hyperedynamic equations in several situations of experimental interest.
Abstract: This is a short review of recent experimental and theoretical studies of phonon interactions in superfluid helium. Phonon--phonon scattering in helium is strongly influenced by the conservation laws and by the peculiarities of the phonon dispersion relation. Theory predicts that because of these factors the spontaneous decay rate varies dramatically with phonon energy, and experiments have confirmed this prediction. The conservation laws can also be used to show that phonon--phonon collisions are predominantly small-angle scattering. We discuss the influence of this special property of phonon collisions on the hydrodynamics of the phonon gas, and we consider the solutions of the hydrodynamic equations in several situations of experimental interest.
TL;DR: In this article, the production of radioactive nuclei during the operation of a light-water reactor is traced, and their decay history is followed, and the potential environmental impacts of this waste are calculated and shown to be comparable to those of other materials we produce.
Abstract: The production of radioactive nuclei during the operation of a light-water reactor is traced, and their decay history is followed. The potential environmental impacts of this waste are calculated and shown to be comparable to those of other materials we produce. Assuming deep burial, it is shown that there are important time delays which prevent the waste from reaching the biosphere in the first few hundred years while its toxicity is decreasing by several orders of magnitude. In the long term, the most important pathway to man was found to be through groundwater into food and water supplies, with consequences calculated to be 0.4 fatalities in ${10}^{6}$ years from each year of all-nuclear power in U.S. Other pathways considered and found to be less important include meteorites, volcanism, release through ground water to airborne particulate, and human intrusion by drilling and mining for unspecified materials and for salt. For time scales longer than ${10}^{6}$ years, nuclear power is shown to reduce man's exposure to radiation by consuming uranium. A cost-benefit analysis is developed for surveillance of buried waste. It is shown that buried high-level waste is environmentally much less dangerous than uranium mill tailings.
TL;DR: In this paper, the authors review the possible contributions to the muon $g$-factor anomaly, which is potentially significant for a comparison between theory and experiment at present, and obtain a total theoretical contribution of 1 165 920.6.
Abstract: We review the possible contributions to the muon $g$-factor anomaly, ${\ensuremath{\alpha}}_{\ensuremath{\mu}}\ensuremath{\equiv}\frac{1}{2}({g}_{\ensuremath{\mu}}\ensuremath{-}2)$ which are potentially significant for a comparison between theory and experiment at present. This includes purely quantum electrodynamic (QED) perturbation theory effects up to eighth order; hadronic effects at fourth and sixth order; and weak interaction effects. From these sources we get a total theoretical contribution ${\ensuremath{\alpha}}_{\ensuremath{\mu}}(\mathrm{theory})=(1 165 920.6\ifmmode\pm\else\textpm\fi{}12.9)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$, to be compared with the latest CERN experimental result (Bailey et al., 1975), ${\ensuremath{\alpha}}_{\ensuremath{\mu}}(\mathrm{experiment})=1 165 895\ifmmode\pm\else\textpm\fi{}27)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$.
TL;DR: The processes leading to end loss of ions from a mirror machine are reviewed in this paper, including breakdown of adiabaticity, scattering and energy drag by classical collisions, and scattering by unstable fluctuations.
Abstract: The processes leading to end loss of ions from a mirror machine are reviewed. These include breakdown of adiabaticity, scattering and energy drag by classical collisions, and scattering by unstable fluctuations. Described are the linear theory of those modes thought to be of significance in present and reactor-size plasmas, and those features known of their nonlinear saturation.
TL;DR: In this paper, the theory of the interaction of electromagnetic radiation with atoms and molecules is outlined, and a fully classical analysis of absorption and emission is formulated in which particular attention is paid to questions of detailed balance and to the sum rules obeyed by the susceptibility.
Abstract: The development of the theory of the interaction of electromagnetic radiation with atoms and molecules is outlined. A fully classical analysis of absorption and emission is formulated in which particular attention is paid to questions of detailed balance and to the sum rules obeyed by the susceptibility. Collision broadening is introduced through time-dependent dipole moment correlation functions, and brief discussions of interruption broadening and various frequency modulation models are given. The corresponding quantum mechanical analysis is presented with emphasis on the points in common with the classical approach. The importance of correspondence principles in bridging the gap between classical and quantum mechanical theories is stressed.
TL;DR: All of the experimental evidence for and against the existence of free, physical quarks from cosmic rays, particle accelerators, and stable matter is reviewed in this paper, with the exception of Niobium pellets of third-integral residual charge.
Abstract: All of the experimental evidence for and against the existence of free, physical quarks from cosmic rays, particle accelerators, and stable matter is reviewed. There is no evidence for the existence of free quarks of fractional charge save for one recent report of niobium pellets of third-integral residual charge. The related searches for quarks of integral charge, for free magnetic monopoles, tachyons, dyons, and other postulated, stable elementary objects are also reviewed. Although some puzzling observations are noted, there is no firm evidence for any of these particles.
TL;DR: Theoretical arguments for the existence of intermediate vector bosons in high-energy nucleon−anti-nucleon collisions are reviewed and the anticipated properties are enumerated in this article.
Abstract: Prospect for the discovery of the charged and neutral intermediate vector bosons in high-energy nucleon---(anti)nucleon collisions are examined. Theoretical arguments for the existence of intermediate bosons are reviewed and the anticipated properties are enumerated. Detailed calculations based on the Drell-Yan model are presented for the production cross sections and for the distributions of decay products. On the basis of these computations the requirement r experimental detectors are assessed.
TL;DR: Kim and Yung-Su Tsai as discussed by the authors reviewed photo pair productions of electrons, muons and heavy leptons and bremsstrahlung of electrons and muons are discussed.
Abstract: Photo pair productions of electrons, muons and heavy leptons and bremsstrahlung of electrons and muons are reviewed. Atomic and nuclear form factors necessary for these calculations are discussed. Straggling of electrons in matter and other effects due to finite target thickness are considered. Tables of radiation lengths of all materials and the energy dependence of photon absorption coefficients of many materials presented, Problems associated with production of particles by photon and electron beams discussed. (Submitted to Rev. of Mod. Physics) * Work supported by the TJ. S. Atomic Energy Commission t This paper supersedes SLAC-PUB-1105, “Photoproduc tion of Electrons, Muons and Heavy Leptons, ” Kwang Je Kim and Yung-Su Tsai, Sept. 1972.
TL;DR: The discovery of the psi particle at SPEAR is reviewed in this paper, where the properties of the particle are discussed as well as the implications of the discovery to the quark model.
Abstract: The discovery of the psi particle at SPEAR is reviewed. The properties of psi are discussed as are the implications of the discovery to the quark model.
TL;DR: In this paper, a review of recent developments in the field of large p/sub T/ physics is presented, with special attention paid to the explanation of the data offered by specific constituent models.
Abstract: Recent developments in the field of large p/sub T/ physics are reviewed. Special attention is paid to the explanation of the data offered by specific constituent models. Emphasis is placed on those data which tend to differentiate between the models. Prospects for better understanding of large p/sub T/ events as the result of new experiments and further theoretical work are discussed.
CERN1
TL;DR: The experiment leading to the discovery of the J particle at the Brookhaven AGS is reviewed in this article, where the design and function of the many detectors employed in the experiment are discussed in some detail.
Abstract: The experiment leading to the discovery of the J particle at the Brookhaven AGS is reviewed. The design and function of the many detectors employed in the experiment are discussed in some detail.
TL;DR: In this paper, the main physical features of LMFBR safety are summarized with particular reference to the maximum possible mechanical energy release in a hypothetical core disruption accident, and it is likely that such a postulated fuel melting accident would lead to a nonenergetic disassembly of the core.
Abstract: The main physical features of LMFBR safety are summarized with particular reference to the maximum possible mechanical energy release in a hypothetical core disruption accident. It is likely that such a postulated fuel melting accident would lead to a nonenergetic disassembly of the core. With pessimistic estimates of reactivity increaases, but not derived from any mechanistic point of view, mechanical energy impacts on the reactor vessel of 100 MJ have been calculated for the Clinch River Breeder Reactor. These are containable with the present design, and the increase should vary only linearly with increased power for future designs of similar concept. Various possible steps are discussed to increase the certainty of these conclusions.
TL;DR: The intersecting storage accelerator at the Brookhaven National Laboratory (ISABELLE) as mentioned in this paper was proposed for the purpose of finding the intermediate vector bosons required for a unified weak and electromagnetic field theory.
Abstract: The intersecting storage accelerator facility ISABELLE proposed for construction at the Brookhaven National Laboratory is reviewed. ISABELLE would permit the exploration of proton--proton collisions at center-of-mass energies continuously variable from 60 to 400 GeV and with luminosities of 10/sup 32/--10/sup 33/ cm/sup -2/ s/sup -1/ over the entire energy range. The facility would consist of two interlaced rings of superconducting magnets, operating at 40 kG, in a common tunnel about 2.6 km in circumference. The proton beams would collide at six intersection regions where particle detecting systems would be located. Protons of about 30 GeV from the AGS will be accumulated in each ring to obtain the design current of 10 A prior to their acceleration to the final energy. In this paper the design philosophy underlying the principal design choices, as well as a brief description of the major accelerator systems and the conventional structures, is presented. An overview of the physics potential provided by ISABELLE is then given. The large extension of the center-of-mass energy range combined with the very high luminosity would provide unique possibilities for the investigation of the questions of greatest current interest in particle physics. Arguments, based on the available data and reasonable theoreticalmore » concepts, are presented that suggest strongly that the intermediate vector bosons required for a unified weak and electromagnetic field theory should be discovered. They should be studied in detail. The hadron production at high transverse momentum, the energy dependence of the strong interactions, and the possible search for new, massive particles are also discussed. The paper concludes with a detailed beam analysis, the various limitations on beam current, the procedures followed in optimizing the luminosity, and a justification of the projected performance levels.« less
TL;DR: In this paper, the authors discuss the origins of the radioactive energy release, and the significance of the life time concept of life-time concept in the context of the first quarter of the twentieth century.
Abstract: Since the discovery of radioactivity predates the birth of quantum mechanics by nearly thirty years, it was inevitable that the most fundamental aspect of radioactive processes, its spontaneity, was also the most baffling one to physicists during the first quarter of the twentieth century. The ensuing struggles in that period with regard to the origins of the radioactive energy release, and to the significance of the life time concept are discussed.