The present status of elastic $\mathrm{pp}$ and $p\overline{p}$ scattering in the high-energy domain is reviewed, with emphasis on the forward and near-forward regions. The experimental techniques for measuring ${\sigma }_{\mathrm{tot}}$, $\rho$, and $B$ are discussed, emphasizing the importance of the region in which the nuclear and Coulomb scattering interfere. The impact-parameter representation is exploited to give simple didactic demonstrations of important rigorous theorems based on analyticity, and to illuminate the significance of the slope parameter $B$ and the curvature parameter $C$. Models of elastic scattering are discussed, and a criterion for the onset of "asymptopia" is given. A critique of dispersion relations is presented. Simple analytic functions are used to fit simultaneously the real and imaginary parts of forward scattering amplitudes for both $\mathrm{pp}$ and $p\overline{p}$, obtained from experimental data for ${\sigma }_{\mathrm{tot}}$ and $\rho$. It is found that a good fit can be obtained using only five parameters (with a cross section rising as ${\ln }^{2}s$), over the energy range $5<\mathrm{}\sqrt{s}<62\mathrm{}$ GeV. The possibilities that (a) the cross section rises only as $\ln s$, (b) the cross section rises only locally as ${\ln }^{2}s$, and eventually goes to a constant value, and (c) the cross-section difference between $\mathrm{pp}$ and $p\overline{p}$ does not vanish as $s\to \infty$ are examined critically. The nuclear slope parameters $B$ are also fitted in a model-independent fashion. Examination of the fits reveals a new regularity of the $p\overline{p}$ and the $\mathrm{pp}$ systems. Predictions of all of the elastic scattering parameters are made at ultrahigh energies, and are compared to the available SPS collider measurements.

A self-contained analysis is given of the simplest quantum fields from the renormalization group point of view: multiscale decomposition, general renormalization theory, resummations of renormalized series via equations of the Callan-Symanzik type, asymptotic freedom, and proof of ultraviolet stability for sine-Gordon fields in two dimensions and for other super-renormalizable scalar fields. Renormalization in four dimensions (Hepp's theorem and the De Calan-Rivasseau $n!$ bound) is presented and applications are made to the Coulomb gases in two dimensions and to the convergence of the planar graph expansions in four-dimensional field theories (t' Hooft-Rivasseau theorem).

The current understanding of the growth of thermal oxide films in terms of the transport properties of the oxides is reviewed. Emphasis is placed on examining quantitative relationships between the film growth rate and other measurable parameters of the oxides. The theories of film growth which are expected to apply in the extreme limits of thick films (Wagner) and thin films (Cabrera and Mott) are outlined. Particular attention is given to examining the expected limits of validity of these theories and to the various ways in which their predictions can be tested experimentally. The growth of a selection of important oxides is then discussed in the light of these two theories. The examples (CoO, NiO, ${\mathrm{Fe}}_3$${\mathrm{O}}_4$, ${\mathrm{Cr}}_2$${\mathrm{O}}_3$, ${\mathrm{Al}}_2$${\mathrm{O}}_3$, and Si${\mathrm{O}}_2$) have been selected such that together they serve to test the theories, have technological relevance, and exhibit a wide variation in behavior. The dominant role of diffusion along oxide grain boundaries in controlling the growth of the crystalline oxides is highlighted.

This paper is a review of the problem of the observable action of enclosed electromagnetic fluxes on the quantum-mechanical state of charged particles, known as the Aharonov-Bohm effect. The authors first describe the quantum effects of the fluxes in the quasiclassical approximation, and discuss their relation with basic quantum-mechanical principles. Then they examine the influence of modeling assumptions on the predicted effects of enclosed fluxes. They analyze the experiments demonstrating the reality of the quantum effects of electromagnetic and gravitational fluxes, and finally discuss the physical significance of these quantum effects, comparing the current interpretation, based on the concept of a nonintegrable phase factor, with alternative approaches.

This paper reviews the progress made in the last several years in understanding the properties of disordered electronic systems. Even in the metallic limit, serious deviations from the Boltzmann transport theory and Fermi-liquid theory have been predicted and observed experimentally. There are two important ingredients in this new understanding: the concept of Anderson localization and the effects of interaction between electrons in a disordered medium. This paper emphasizes the theoretical aspect, even though some of the relevant experiments are also examined. The bulk of the paper focuses on the metallic side, but the authors also discuss the metal-to-insulator transition and comment on problems associated with the insulator.

This paper presents a review of both active and passive ring laser devices. The operating principles of the ring laser are developed and discussed, with special emphasis given to the problems associated with the achievement of greater sensitivity and stability. First-principle treatments of the nature of quantum noise in the ring laser gyro and various methods designed to avoid low-rotation-rate lock-in are presented. Descriptions of state-of-the-art devices and current and proposed applications (including a proposed test of metric theories of gravity using a passive cavity ring laser) are given.

A so-called representation (rep) group G is introduced which is formed by all the $\left|\mathrm{G}\right|$ distinct operators (or matrices) of an abstract group Ĝ in a rep space $L$ and which is an $m$-fold covering group of another abstract group g. G forms a rep of Ĝ. The rep group differs from an abstract group in that its elements are not linearly independent and thus the number $n$ of its linearly independent class operators is less than its class number $N$. A systematic theory is established for the rep group based on Dirac's CSCO (complete set of commuting operators) approach in quantum mechanics. This theory also comprises the rep theory for abstract groups as a special case of $m=1\mathrm{}$. Three kinds of CSCO, the CSCO-I, -II, and -III, are defined which are the analogies of $J^2$, ($J^2$,$J_z$), and ($J^2$,$J_z$,${\overline{J}}_z$), respectively, for the rotation group S${\mathrm{O}}_3$, where ${\overline{J}}_z$ is the component of angular momentum in the intrinsic frame. The primitive characters, the irreducible basis and Clebsch-Gordan coefficients, and the irreducible matrices of the rep group G in any subgroup symmetry adaptation can be found by solving the eigenequations of the CSCO-I, -II, and -III of G, respectively, in appropriate vector spaces. It is shown that the rep group G has only $n$ instead of $N$ inequivalent irreducible representations (irreps), which are just the allowable irreps of the abstract group Ĝ in the space $L$. Therefore, the construction of the irreps of Ĝ in $L$ can be replaced by that of G. The labor involved in the construction of the irreps of the rep group G with order $\left|\mathrm{G}\right|$ is no more than that for the group g with order $\left|\mathrm{g}\right|=\frac{\left|\mathrm{G}\right|}{m}$, and thus tremendous labor can be saved by working with the rep group G instead of the abstract group Ĝ. Based on the rep-group theory, a new approach to the space-group rep theory is proposed, which is distinguished by its simplicity and applicability. Corresponding to each little group G(k), there is a rep group ${\mathbf{G}\prime }_{\mathrm{k}}$. The $n$ inequivalent irreps of ${\mathbf{G}\prime }_{\mathrm{k}}$ are essentially just the acceptable irreps of the little group G(k). Consequently the construction of the irreps of G(k) is almost as easy as that of the little co-group ${\mathbf{G}}_0$(k). An easily programmable algorithm is established for computing the Clebsch-Gordan series and Clebsch-Gordan coefficients of a space group simultaneously.

This paper reviews the experimental and theoretical studies of breakup processes induced by He projectiles. For this type of reaction knowledge of three-body kinematics is imperative; hence important aspects are summarized. Although some nuclear structure information has been studied with this type of reaction, the emphasis of this review is mainly on the reaction mechanism. The phenomena described here are quite general, so the consequences for other projectiles (i.e., heavy ions) are also discussed.

This paper briefly describes the hydrothermal growth process and then discusses the important defects in quartz (twins, inclusions, dislocations, and impurities) and the correlations among them. The properties of quartz are reviewed and tabulated under the headings of intrinsic properties and defect-related properties. Resonator theory and fabrication techniques are outlined, with particular reference to aspects related to defects in the crystals. At this stage, it is possible to list the circuit design factors which must be taken into account when the application calls for very high performance. The paper then looks at the approach of a device maker faced with problems caused by impurities, inclusions, dislocations, and other nonideal properties of real crystals. This question leads to a specification of the crystals suitable for device use. The major parameter of this specification is the infrared $Q$, which must exceed about 1.8 million for satisfactory performance and yield. Acceptance test procedures are discussed, and finally the present state of the subject and the future prospects are briefly described.

This paper reviews the theory of inflationary universe models, giving particular emphasis to the question of origin and growth of energy-density fluctuations in these new cosmologies. The first four sections constitute a pedagogical introduction to some of the important quantum field theory methods used in inflationary universe scenarios: calculation of the effective potential, finite-temperature quantum field theory, analysis of the decay of a metastable quantum state, and free field theory in curved space-time.

Since the discovery by Steglich et al. (1979) of superconductivity in the high-effective-mass ($\sim 200m_e$) electrons in Ce${\mathrm{Cu}}_2$${\mathrm{Si}}_2$, the search for and characterization of such "heavy-fermion" systems has been a rapidly growing field of study. The eight heavy-fermion systems known to date include superconductors (Ce${\mathrm{Cu}}_2$${\mathrm{Si}}_2$, U${\mathrm{Be}}_{13}$, U${\mathrm{Pt}}_3$), magnets (Np${\mathrm{Be}}_{13}$, ${\mathrm{U}}_2$${\mathrm{Zn}}_{17}$, U${\mathrm{Cd}}_{11}$), and materials in which no ordering is observed (Ce${\mathrm{Al}}_3$, Ce${\mathrm{Cu}}_6$). These $f$-electron materials have, in comparison to normal metals, enormous specific heat $\gamma$ values (450-1600 mJ/mol ${\mathrm{K}}^2$), large values of the low-temperature magnetic susceptibility $\chi$ (8-50×${10}^{-3\mathrm{}}$ emu/mol G), maxima in the resistivity at low temperatures with large ${\rho }_{max}$ values (100-200 μΩ cm), and unusual temperature dependences of their specific heats below 10 K. The three heavy-fermion superconductors show such unusual behavior that the possibility of $p$-wave pairing of the superconducting electrons, rather than the usual BCS $s$-wave pairing, cannot be ruled out. This paper reviews the experimental results to date, to serve both as a status report and as a starting point for future research. Several correlations between properties are pointed out, including the observation that a low value of the Wilson ratio ($\sim \frac{\chi }{\gamma }$) appears to correlate with the occurrence of superconductivity.

The problem of long-time predictions in many-dimensional Hamiltonian systems is examined. Some geometrical methods of nonlinear dynamics are reviewed, and applied to the study of a class of instabilities that are peculiar of systems with more than two degrees of freedom. These are called "weak instabilities," since they manifest themselves only after a long time. A qualitative analysis of the weak instability induced by slow parametric modulation (the modulational diffusion) is developed. The relevance of these phenomena to the problem of stability of charged particles in accelerators and storage rings is discussed.

This paper reviews recent work related to modulational instability and wave envelope self-focusing in dynamical and statistical systems. After introductory remarks pertinent to nonlinear optics realizations of these effects, the author summarizes the status of the subject in plasma physics, where it has come to be called "strong Langmuir turbulence." The paper treats the historical development of pertinent concepts, analytical theory, numerical simulations, laboratory experiments, and spacecraft observations. The role of self-similar self-focusing Langmuir envelope wave packets is emphasized, both in the Zakharov equation model for the wave dynamics and in a statistical theory based on this dynamical model.

Eichten et al. summarize the motivation for exploring the 1-TeV (=${10}^{12}$ eV) energy scale in elementary particle interactions and explore the capabilities of proton-(anti)proton colliders with beam energies between 1 and 50 TeV. The authors calculate the production rates and characteristics for a number of conventional processes, and discuss their intrinsic physics interest as well as their role as backgrounds to more exotic phenomena. The authors review the theoretical motivation and expected signatures for several new phenomena which may occur on the 1-TeV scale. Their results provide a reference point for the choice of machine parameters and for experiment design.

This paper is focused mainly on the subject of elastic magnetic electron scattering and how it has come to be a useful tool for studying the spatial distributions of convection and magnetization currents in the nuclear ground state. Using such a probe, emphasis is clearly placed on the electromagnetic currents provided by the valence nucleons in the nucleus, indeed, by neutrons as well as protons. These do not yield a complete description of the problem, however, and more complex nuclear many-body configurations are generally required. Various models are employed (shell-model configuration mixing, core-polarization effects, models of deformed nuclei, for instance), giving rise to quantitative comparisons with experimental measurements. Moreover, to achieve such successful descriptions, especially at high momentum transfers, it is frequently necessary to go beyond a purely one-body nucleonic reaction mechanism and to include the effects of two-body meson-exchange currents based on non-nucleonic degrees of freedom ($\pi$,$\rho$,$\Delta ,\dots$). The authors discuss all of these various facets of the problem, beginning with surveys of the historical development of the field and of the experimental techniques employed in such studies. They present a detailed treatment of the formalism needed in discussions of elastic electron scattering, including an introduction to the density-matrix approach to the nuclear many-body problem, with simple examples to clarify the ideas involved. For the nonspecialist a separate section of illustrative examples is supplied in which qualitative discussions of various aspects of the physics accessible in such ($e$,$e^{\prime }$) studies are highlighted. Experimental and theoretical results for a large number of nuclei ranging from $A=2\mathrm{} \mathrm{to} 209$ are described in detail; this represents a compilation of virtually all of the high-quality data that are available at present. The paper concludes with projections as to which directions may be followed in the future, in particular, with a relatively complete discussion of the use of polarization in elastic electron scattering.

This review covers the experimental and theoretical progress over the last 15 years in the study of systems of interacting Josephson junctions. Such systems are of interest for device applications and for investigations of nonequilibrium phenomena in superconductors. In the description of coupled Josephson elements the emphasis is on the "physics" involved in a number of interaction mechanisms and not so much on the technical problems encountered in the construction of arrays of coupled juntions.

A review of our present understanding of the global climate system, consisting of the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere, and their complex interactions and feedbacks is given from the point of view of a physicist. This understanding is based both on real observations and on the results from numerical simulations. The main emphasis in this review is on the atmosphere and oceans. First, balance equations describing the large-scale climate and its evolution in time are derived from the basic thermohydrodynamic laws of classical physics. The observed atmosphere-ocean system is then described by showing how the balances of radiation, mass, angular momentum, water, and energy are maintained during present climatic conditions. Next, a hierarchy of mathematical models that successfully simulate various aspects of the climate is discussed, and examples are given of how three-dimensional general circulation models are being used to increase our understanding of the global climate "machine." Finally, the possible impact of human activities on climate is discussed, with main emphasis on likely future heating due to the release of carbon dioxide in the atmosphere.

This review of the properties of leptons, mesons, and baryons is an updating of the Review of Particle Properties, Particle Data Group [Phys. Lett. 111B (1982)]. Data are evaluated, listed, averaged, and summarized in tables. Numerous tables, figures, and formulae of interest to particle physicists are also included. A data booklet is available.

Powerful extragalactic radio sources comprise two extended regions containing magnetic field and synchrotron-emitting relativistic electrons, each linked by a jet to a central compact radio source located in the nucleus of the associated galaxy. These jets are collimated streams of plasma that emerge from the nucleus in opposite directions, along which flow mass, momentum, energy, and magnetic flux. Methods of using the observations diagnostically to infer the pressures, densities, and fluid velocities within jets are explained. The jets terminate in the extended radio components, where they interact strongly with the surrounding medium through a combination of shock waves and instabilities. Jets may expand freely, be confined by external gas pressure, or be pinched by toroidal magnetic fields. Shear flows are known to be Kelvin-Helmholtz unstable and thus may be responsible for some of the observed oscillation of jets about their mean directions and for creating the turbulence and shock waves needed to accelerate the relativistic electrons. Larger-scale bending may be caused by changes in the jet axis within the nucleus, gravitational interaction of the radio galaxy with a companion galaxy, or rapid motion of the source through dense intergalactic gas. The compact radio sources also exhibit a jet morphology and contain more direct clues as to the origins of jets; in particular, the variations sometimes observed imply bulk flows that are relativistic. It is widely believed that nuclear activity is ultimately ascribable to gas accreting onto a massive black hole. The accretion can proceed in several different fashions, depending upon whether or not the gas has angular momentum and whether or not the radiation emitted is sufficiently intense to influence the dynamics of the flow. Several distinct mechanisms for jet production in the context of black holes have been proposed. (Alternative mechanisms involving dense star clusters and massive spinning stars are also reviewed.) Supersonic jets may be collimated along the spin axis of a gas cloud surrounding the source of the lighter jet gas. Magnetic fields may be crucial in collimating jets, especially if they are wrapped around the jet by orbiting gas and can thereby collimate the outflow through the pinch effect. In fact, the spin energy of the black hole could also be extracted by magnetic torques, in which case the jet would contain electrons and positrons and carry a large electromagnetic Poynting flux. Statistical investigations of active galaxies also furnish valuable information on their nature and evolutionary behavior. The formation of particular kinds of sources appears to be correlated with environmental effects and cosmic epoch. In addition, the brightest compact radio sources on the sky, which probably involve relativistic motion, may be intrinsically faint objects beamed in our direction. There is now compelling evidence for the continuous fueling of extragalactic radio sources through jets emerging from the nucleus of the associated galaxy. The morphological classification of radio sources is interpreted in terms of the powers, speeds, and surroundings of jets. The ratio of the mass accretion rate to the mass of the hole may determine whether an active nucleus will be primarily a thermal object like an optical quasar or a nonthermal object like a radio galaxy. The authors outline a unified model of nuclear activity and assess what future progress may stem from observational developments (especially the proposed very long baseline array), experimental approaches (such as wind tunnel simulations), and theoretical studies (in particular, large-scale numerical hydrodynamical computing).