Showing papers in "Physics Today in 1992"
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TL;DR: Physics of Climate as mentioned in this paper is a suitable text for at least part of a general circulation course and the quantity and quality of information in this book are such that anyone involved in the study of the atmosphere or climate will wish to have it handy.
Abstract: Physics of Climate is a suitable text for at least part of a general circulation course. The quantity and quality of information in this book are such that anyone involved in the study of the atmosphere or climate will wish to have it handy. In particular, anyone working with a general circulation model will want to see how his model compares with the observed world. Eight chapters are the core of the text. They cover: data description; observed states of the atmosphere, ocean, and cryosphere; exchanges between the atmosphere and the surface; and the budgets of water, angular momentum, and energy.
2,030 citations
TL;DR: The Kinetic Theory of Gases as discussed by the authors describes the physical structure of surfaces and their properties, including surface curvature, surface tension, and surface mobility, as well as surface chemistry.
Abstract: SURFACE STRUCTURE, THERMODYNAMICS, AND MOBILITY. Atomic Structure of Surfaces. Electronic Structure of Surfaces. Surface Tension. Thermodynamics of One-Component Systems. Thermodynamics of Multicomponent Systems. Surface Mobility. GAS-SURFACE INTERACTIONS. The Kinetic Theory of Gases. Molecular Beam Formation. Gas Scattering. Adsorption-The Kinetic View. Physical Adsorption. Chemisorption. Surface Chemical Reactions. ENERGETIC PARTICLE-SURFACE INTERACTIONS. Electron-Surface Interactions. Ion-Surface Interactions. Photon-Surface Interactions. CRYSTAL GROWTH. Crystal Nucleation and Growth. Index.
376 citations
TL;DR: Cordey and Parker as mentioned in this paper proposed the fusion reaction with the highest cross section using the deuterium and tritium isotopes of hydrogen, and D‐T would be the fuel of choice for the first generation of fusion reactors.
Abstract: For the past four decades, scientists throughout the world have pursued the dream of controlled thermonuclear fusion. The attraction of this goal is the enormous energy that is potentially available in fusion fuels and the view of fusion as a safe, clean energy source. The fusion reaction with the highest cross section uses the deuterium and tritium isotopes of hydrogen, and D‐T would be the fuel of choice for the first generation of fusion reactors. (See the article by J. Geoffrey Cordey, Robert J. Goldston and Ronald R. Parker, January, page 22.)
371 citations
TL;DR: In this paper, Monte Carlo programs for lattice models using supercomputers are vectorized using Monte Carlo methods for improved efficiency of computer simulations in statistical mechanics, including simulation of random growth processes.
Abstract: Vectorisation of Monte Carlo programs for lattice models using supercomputers.- Parallel algorithms for statistical physics problems.- New monte carlo methods for improved efficiency of computer simulations in statistical mechanics.- Simulation of random growth processes.- Recent progress in the simulation of classical fluids.- Monte Carlo techniques for quantum fluids, solids and droplets.- Quantum lattice problems.- Simulations of macromolecules.- Percolation, critical phenomena in dilute magnets, cellular automata and related problems.- Interfaces, wetting phenomena, incommensurate phases.- Spin glasses, orientational glasses and random field systems.- Recent developments in the Monte Carlo simulation of condensed matter.
320 citations
TL;DR: In this article, the authors present a rigorous treatment of the first principles of the algebraic and analytic core of quantum field theory and correlate modern mathematical theory with the explanation of the observed process of particle production and of particle-wave duality.
Abstract: The authors present a rigorous treatment of the first principles of the algebraic and analytic core of quantum field theory Their aim is to correlate modern mathematical theory with the explanation of the observed process of particle production and of particle-wave duality that heuristic quantum field theory provides Many topics are treated here in book form for the first time, from the origins of complex structures to the quantization of tachyons and domains of dependence for quantized wave equations This work begins with a comprehensive analysis, in a universal format, of the structure and characterization of free fields, which is illustrated by applications to specific fields Nonlinear local functions of both free fields (or Wick products) and interacting fields are established mathematically in a way that is consistent with the basic physical constraints and practice Among other topics discussed are functional integration, Fourier transforms in Hilbert space, and implementability of canonical transformations The authors address readers interested in fundamental mathematical physics and who have at least the training of an entering graduate student A series of lexicons connects the mathematical development with the underlying physical motivation or interpretation The examples and problems illustrate the theory and relate it to the scientific literatureOriginally published in 1992The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905
293 citations
TL;DR: Calabi-Yau spaces are complex spaces with a vanishing first Chern class, or equivalently, with trivial canonical bundle (canonical class) as discussed by the authors, which are used to construct possibly realistic (super)string models and are thus being studied vigorously in the recent physics literature.
Abstract: Calabi-Yau spaces are complex spaces with a vanishing first Chern class, or equivalently, with trivial canonical bundle (canonical class). They are used to construct possibly realistic (super)string models and are thus being studied vigorously in the recent physics literature.In the main part of the Book, collected and reviewed are relevant results on (1) several major techniques of constructing such spaces and (2) computation of physically relevant quantities such as massless field spectra and their Yukawa interactions. Issues of (3) stringy corrections and (4) moduli space and its geometry are still in the stage of rapid and continuing development, whence there is more emphasis on open problems here. Also is included a preliminary discussion of the conjectured universal moduli space and related open problems. Finally, several detailed models and sample computations are included throughout the Book to exemplify the techniques and the general discussion.The Book also contains a Lexicon (28 pages) of 150 assorted terms, key-words and main results and theorems, well suited for a handy reference. Although cross-referenced with the main part of the Book, the Lexicon can also be used independently.The level of mathematics is guided and developed between that of the popular Physics Reports of Eguchi, Gilkey and Hanson and the book Superstrings (Vol. 2) by Green, Schwarz and Witten on one end and Principles of Algebraic Geometry of Griffiths and Harris on the other.This is the first systematic exposition in book form of the material on Calabi-Yau spaces, related mathematics and the physics application, otherwise scattered through research articles in journals and conference proceedings.
205 citations
TL;DR: In this article, the authors describe concepts for such a power plant, its beneficial features and a low-cost reactor test facility for developing practical fusion power, which is based on different physics and technology from a magnetic fusion power plant and therefore presents somewhat different benefits and challenges.
Abstract: Fusion is potentially a safe clean source not limited by political boundaries. Magnetic and inertial fusion share this promise, but there are differences between them. An inertial fusion power plant is based on different physics and technology from a magnetic fusion power plant and therefore presents somewhat different benefits and challenges. The facilities required to demonstrate inertial fusion power are potentially much smaller. In this article we describe concepts for such a power plant, its beneficial features and a low‐cost reactor test facility for developing practical fusion power.
174 citations
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TL;DR: In this article, an introduction to fiber optic sensor technology and some of the applications that make this branch of optic technology, which is still in its early infancy, an interesting field.
Abstract: Fiber optic sensor technology offers the possibility of sensing different parameters like strain, temperature, pressure in harsh environment and remote locations. these kinds of sensors modulates some features of the light wave in an optical fiber such an intensity and phase or use optical fiber as a medium for transmitting the measurement information. The advantages of fiber optic sensors in contrast to conventional electrical ones make them popular in different applications and now a day they consider as a key component in improving industrial processes, quality control systems, medical diagnostics, and preventing and controlling general process abnormalities. This paper is an introduction to fiber optic sensor technology and some of the applications that make this branch of optic technology, which is still in its early infancy, an interesting field. Keywords—Fiber optic sensors, distributed sensors, sensor application, crack sensor.
169 citations
TL;DR: In this paper, the structure of quantized vortices is described and a nucleation procedure for quantized V2V arrays is proposed, which is based on quantum turbulence and mutual friction.
Abstract: Preface 1. Background on classical vortices 2. Background on liquid helium II 3. Vortex dynamics and mutual friction 4. The structure of quantized vortices 5. Vortex arrays 6. Vortex waves 7. Quantum turbulence 8. Nucleation of quantized vortices Index.
163 citations
TL;DR: Transition Amplitudes in Electrodynamics A Survey of Some Interaction Processes between Photons and Atoms Nonperturbative Calculation of Transition Amplitudes Radiation Considered as a Reservoir Master Equation for the Particles Optical Bloch Equations The Dressed Atom Approach as mentioned in this paper
Abstract: Transition Amplitudes in Electrodynamics A Survey of Some Interaction Processes Between Photons and Atoms Nonperturbative Calculation of Transition Amplitudes Radiation Considered as a Reservoir Master Equation for the Particles Optical Bloch Equations The Dressed Atom Approach.
TL;DR: Carbon 60 is a fascinating and arrestingly beautiful molecule with 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer-ball-like structure that belongs to the icosahedral point group Ih as mentioned in this paper.
Abstract: Carbon 60 is a fascinating and arrestingly beautiful molecule. With 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer‐ball‐like structure that belongs to the icosahedral point group Ih, its high symmetry alone invites special attention. The publication in September 1990 of a simple technique for manufacturing and concentrating macroscopic amounts of this new form of carbon (see Donald R. Huffman's article in PHYSICS TODAY, November 1991, page 22) announced to the scientific community that enabling technology had arrived. Macroscopic amounts of C60 (and the higher fullerenes, such as C70 and C84) can now be made with anapparatus as simple as an arc furnace powered with an arc welding supply. Accordingly, chemists, physicists and materials scientists have joined forces in an explosion of effort to explore the properties of this unusual molecular building block.
TL;DR: The physics of the conversion of the electronic excitation energy into mechanical and chemical energy links atomic physics in a solid at low excitation densities to nanometer-scale continuum mechanics at high excitation density.
Abstract: The surprising fact that even very complex molecules can be ejected intact into the vapor phase when a material is electronically excited by incident particles provides a new probe of the behavior of condensed matter at high excitation densities. The physics of the conversion of the electronic excitation energy into mechanical and chemical energy links atomic physics in a solid at low excitation densities to nanometer‐scale continuum mechanics at high excitation densities
TL;DR: The development of compact, reliable and inexpensive short-wavelength lasers is certain to have profound effects on virtually any technology that uses coherent visible light as discussed by the authors, and the primary driving force behind efforts to develop blue-green diode lasers is without question optical recording.
Abstract: The development of compact, reliable and inexpensive short‐wavelength lasers is certain to have profound effects on virtually any technology that uses coherent visible light. Although the impact of such devices will be far‐reaching, the primary driving force behind efforts to develop blue‐green diode lasers is without question optical recording. The demand for increased data storage capabilities is continually forcing the recording industry to increase storage densities.
TL;DR: Modeling the function of the cochlea is the part of the inner ear that converts acoustic signals to the neural code that conveys auditory information to the brain.
Abstract: Understanding human perception is at the forefront of scientific research goals today. The development of robots, virtual reality, speech coders and speech recognition devices depends on a good understanding of how we hear. The cochlea is the part of the inner ear that converts acoustic signals to the neural code that conveys auditory information to the brain. Modeling the function of the cochlea has been an active area of research since the development of the digital computer, yet several mysteries remain.
TL;DR: Whether natural or synthetic, for a composite system to function efficiently its components must be assembled into a specific architecture that gives the required spectrum of properties.
Abstract: Many advanced composites can best be described hierarchically. In particular, the biological composites that occur in organisms are generally seen to be organized on discrete scale levels ranging from the molecular to the macroscopic. At each level the components are held together by specific interactions and organized in a way that is optimized for the ultimate function and performance of the overall system. Biological composites typically consist of fibers made from long macromolecules, organized into different structures. One can learn much from biological composites by considering the relationship between their structures and their properties. Whether natural or synthetic, for a composite system to function efficiently its components must be assembled into a specific architecture that gives the required spectrum of properties.
TL;DR: In this paper, the fundamental principles of holography sufficient for the creation of new types of 3D cinematography and artificial intelligence are discussed, as well as the application of holographic optical elements for use with semiconductor lasers.
Abstract: Integrated optics - OEICs or PICs?, H.Kogelnik quantum opto-electronics for optical processing, D.A.B.Miller optics in telecommunications - beyond transmission, P.W.E.Smith microoptics, K.Iga holographic optical elements for use with semiconductor lasers, H.P.Herzig and R.Dadliker fiber optic signal processing, B.Culshaw and I.Adonovic optical memories, Y.Tsunado what are photorefractives good for?, H.Rajbenbach and J.-P.Huignard adaptive interferometry - a new area of applications of photorefractive crystals, S.I.Stepanov water wave optics, J.J.Stamnes about the philosophies of diffraction, A.W.Lohmann the essential journals of optics, J.N.Howard optics in China - ancient and modern accomplishments, Z.-M.Zhang unusual optics - optical interconnects as learned from the eyes of (nocturnal insects), crayfish, shellfish and similar creatures, P.Greguss the opposition effect in volume and surface scattering, K.C.Dainty influence of source-correlations on spectra of radiated fields, E.Wolf quantum statistics and coherence of nonlinear optical processes, J.Perina one photon light-pulses versus attenuated classical light-pulses, A.Aspect and P.Grangier optical propagation through the atmosphere, A.Consortini are the fundamental principles of holography sufficient for the creation of new types of 3D cinematography and artificial intelligence?. Y.N.Denisyuk medical applications of holographic 3D display, J.Tsujiuchi Moire fringes and their applicatons, O.Bryngdahl breaking the boundaries of optical system design and construction , C.H.F.Velzel interferometry - what's new since Michelson?, P.Hariharan curreent trends in optical testing, D.Malacara adaptive optics, F.Merkel triple correlations and dispectra in high-resolution astonomical imaging. H.Weigelt phase retrieval imaging problems, J.R.Fienup blind deconvolution - recovering the seemingly irrecoverable!, R.H.T.Bates and H.Jiang pattern recognition, similarity, neural nets, and optics, H.H.Arsenault and Y.Sheng towards nonlinear optical processing, T.Szoplik and K.Chalasinska-Macukow new apects of optics for optical computing, V.Morozov digital optical computing, S.D. Smith computing - a joint venture for light and electricity?, P.Chavel.
TL;DR: The oceans play a vital role in global temperature changes, storing both heat and greenhouse gases as discussed by the authors, and without the oceans the atmosphere would warm at two to three times greater a rate, other factors remaining equal.
Abstract: The release of carbon dioxide and other greenhouse gases into the atmosphere is associated with temperature changes in both the atmosphere and the oceans. The oceans play a vital role in global temperature changes, storing both heat and greenhouse gases. Without the oceans the atmosphere would warm at two to three times greater a rate, other factors remaining equal. To understand and predict global warming, then, it is important to measure, rather than just speculate on, changes in the heat content of the ocean.
TL;DR: In this article, the authors proposed a heterojunction injection laser, which has had a great technological impact in areas ranging from optical communications to the compact-disc player, and demonstrated its ability to operate continuously at room temperature.
Abstract: Junctions between dissimilar semiconductors have long attracted the attention of researchers in solid‐state physics and electronics. The additional degree of freedom provided by the two materials in the semiconductor heterojunction offers opportunities to pursue new phenomena and applications not possible with homogeneous media. A notable example is the heterojunction injection laser, which, because of its ability to operate continuously at room temperature, has had a great technological impact in areas ranging from optical communications to the compact‐disc player.
TL;DR: Gibbons and Blair as mentioned in this paper pointed out that the long time required to develop and implement new large-scale energy technologies, on the order of decades,underscores the urgency of the need to accelerate development of alternative energy sources.
Abstract: Nearly 90% of the world's energy needs are today supplied by fossil fuels Long‐term reliance on fossil‐fuel energy sources, however, is acknowledged to be a dangerous strategy—despite the large reserves of coal available in the US and elsewhere Use of fossil fuels exacerbates pollution and acid rain and heightens the risk of global warming by adding CO2 to the atmosphere Society will be served best if energy production in the next century uses environmentally attractive methods that do not involve the combustion of fossil fuels (See the article by John H Gibbons and Peter D Blair in PHYSICS TODAY, July 1991, page 22) The long time required to develop and implement new large‐scale energy technologies—on the order of decades—underscores the urgency of the need to accelerate development of alternative energy sources
TL;DR: The magnetic multilayers as mentioned in this paper are magnetic superlattices that exhibit more new and interesting physical effects than any other artificially made material system and have the potential for many technological advances in information storage and retrieval and in the synthesis of new magnets for a variety of applications.
Abstract: Artificially made, ordered material systems are a pillar of late‐20th‐century advanced technology. In principle, metallic magnetic superlattices—also called magnetic multilayers—should exhibit more new and interesting physical effects than any other artificially made material system. This gives them the potential for many technological advances in information storage and retrieval and in the synthesis of new magnets for a variety of applications.
TL;DR: The growth of commerce around the end of the 16th century created a need for large amounts of numerical calculation, which stimulated Leibniz, Pascal and others to invent mechanical adding and multiplying machines in the 17th century.
Abstract: The growth of commerce around the end of the 16th century created a need for large amounts of numerical calculation. the increasing understanding of astronomical phenomena around the same time also depended on accurate computation. the difficulty of accurately performing large amounts of tedious numerical work by hand stimulated Leibniz, Pascal and others to invent mechanical adding and multiplying machines in the 17th century. (See figure 1.) the speed and complexity of mechanical computation were limited by inertia, friction, size and the difficulty of transmitting information very far. the development of electrical technology led to the introduction of electrical components in peripheral parts of computing machines, such as motors in place of hand cranks. Major improvements in performance, however, had to await the electrical representation of information
TL;DR: In this paper, the superconductivity at 40 K in cuprates of yttrium, bismuth, and thallium was shown to be achievable at higher temperatures than the all-important 77 K boiling point of liquid nitrogen.
Abstract: After the discovery of superconductivity at 40 K in cuprates by Georg Bednorz and Alex Muller in 1986, many researchers became involved in the synthesis of new higher‐temperature superconductors. I believe that many of them failed in this quest simply because they did not realize that the crystal chemistry of such materials is extremely complicated. By the following spring, of course, groups all over the world were fabricating new superconducting cuprates of yttrium, bismuth and thallium that allowed critical temperatures to exceed the all‐important 77‐K boiling point of liquid nitrogen. But because of the complex crystal chemistry involved, it will take a long time to optimize the superconducting properties of these cuprates for the development of useful superconducting wires. Thin films of superconducting cuprates, by contrast, are already quite close to being commercially available for SQUIDS and microwave applications.
TL;DR: Alvarez, his son Walter, Frank Asaro and Helen Michel of the University of California, Berkeley as discussed by the authors raised a hypothesis that was literally out of this world: Could a massive comet or asteroid, perhaps 10 km in diameter, have struck the Earth about 65 million years ago, changing the climate so drastically that the dinosaurs and other creatures could no longer survive?
Abstract: The search started with a hypothesis that was literally out of this world: Could a massive comet or asteroid, perhaps 10 km in diameter, have struck the Earth about 65 million years ago, changing the climate so drastically that the dinosaurs and other creatures could no longer survive? That question was raised in 1980 by Luis Alvarez, his son Walter, Frank Asaro and Helen Michel of the University of California, Berkeley. Their evidence at the time was scanty: only an anomalous concentration of iridium at the geological stratum corresponding to the era when the giant reptiles became extinct and supposedly delivered by the extraterrestrial projectile. (See the article by Luis Alvarez in PHYSICS TODAY, July 1987, page 24.) But the suggestion triggered a massive hunt, and geological sleuths soon gathered much substantiating evidence. The telltale crater, however, remained elusive.
TL;DR: In this article, it was shown that almost all of our information about the universe beyond Earth comes from photons (visible photons from stars, xray photons from hot plasmas, radio photons from the 21-cm hyperfine transition in hydrogen, microwave photons from cosmic background radiation and so forth).
Abstract: Almost all of our information about the universe beyond Earth comes from photons—visible photons from stars, xray photons from hot plasmas, radio photons from the 21‐cm hyperfine transition in hydrogen, microwave photons from the cosmic background radiation and so forth.