bluuebunny/crossref_metadata_2025 huggingface dataset:
X-Ray Stars Identified As Blue Stellar Objects
Authors: Thomsen Dietrick E.
Published: April 2009

Point sources of cosmic x rays have now been identified with bluish starlike objects in two cases—Scorpio X-l and Cygnus X-2. The Sco X-l identification was established after precise observations of position were made on a rocket flight on 8 March 1966. The position data were published by Herbert Gursky, Riccardo Giacconi, P. Gorenstein and J. R. Waters of American Science and Engineering, and Minoru Oda, H. Bradt, G. Garmire and B. V. Sreekantan of MIT in The Astrophysical Journal for October (page 310). Identification of Cygnus X-2 results from a rocket flight of 11 Oct. 1966 by the ASE group and was announced by Giacconi at the Texas [sic] Symposium on Relativistic Astrophysics, which was held in New York from 23 to 27 Jan. The second identification prompted Giacconi to hazard the remark: “If you want to make statistics on two objects, this could establish the existence of a new class of objects with main emission in the x-ray region through some part of their lives.”
SLAC: The accelerator
Authors: Neal Richard B.
Published: April 2009

LAST MAY, APPROXIMATELY four years after construction started at the Stanford Linear Accelerator Center, a beam traveled the entire two-mile length of the accelerator from an injector at the west end to a beam dump at the east end. This machine is distinguished not only by its length and high energy (20 GeV); it also produces high current (30 microamperes), exceeding by a factor of 100 that of any other machine operating with an energy greater than 10 GeV. Moreover the design permits future expansion (from stage I to stage II) that will double both energy and current by adding radiofrequency sources along the length. Details of the design evolution appear in references 1–5.
Nagaoka to Rutherford, 22 February 1911
Authors: Badash Lawrence
Published: April 2009

WHAT WAS PHYSICS LIKE slightly more than half a century ago? One readily thinks of such famous names as J. J. Thomson, Ernest Rutherford, Marie Curie, Max Planck, Niels Bohr, H. A. Lorentz, Albert Einstein, et al., but these are the highlights of hindsight. For the background of perhaps lesser, but nevertheless significant and interesting efforts, we usually must look to the contemporary literature, since histories of science rarely have room for elaborate descriptions of a period.
Oblate Sun Supports Scalar-Tensor Theory
Authors: Lubkin Gloria B.
Published: April 2009

One of the three classical tests of Einstein's gravitational theory has been its prediction of Mercury's orbit; the Einstein value agreed with observations to within 1%. Now measurements by Robert H. Dicke and Mark Goldenberg of Princeton University show that the sun is slightly elliptical in shape. The quadrupole moment indicated by such a solar oblateness would perturb Mercury's motion and could account for 8% of the classical excess in the precession of Mercury's perihelion; this would imply an 8% discrepancy in the Einstein value. The other two tests of Einstein's theory are the gravitational red shift, which is also predicted by other theories, and the gravitational deflection of light, which is poorly known.
Superconductor Acts as Phonon Generator and Detector
Authors: Lubkin Gloria B.
Published: April 2009

If you excite quasi-particles in a superconductor, you can generate and detect phonons. Aly Dayem and Wolfgang Eisenmenger, who reported their work in the 23 Jan. issue of Phys. Rev. Letters, have built such a quantum generator and detector of phonons at 300 GHz. The same technique can be used over a large frequency range where conventional generators and detectors become prohibitively difficult. Until now phonons have been generated only piezoelectrically and at much lower frequencies.
Nuclear structure and modern research
Authors: Weisskopf Victor F.
Published: April 2009

IN THE EXPLORATION of the structure of matter in the last decades we have witnessed three steps: first, the exploration of the electron shells of the atom; second, investigation of the structure of the nucleus; and third, the beginning of the exploration of the structure of the nucleon, the constituent of the nucleus.
Nonlinear problems in physics
Authors: Heisenberg Werner
Published: April 2009

NONLINEAR PROBLEMS in physics are difficult to discuss for several reasons. First, what are nonlinear problems? Practically every problem in theoretical physics is governed by nonlinear mathematical equations, except perhaps quantum theory, and even in quantum theory it is a rather controversial question whether it will finally be a linear or nonlinear theory. Therefore by far the largest part of theoretical physics is devoted to nonlinear problems.
The AIP in 1966
Authors: Hodes Bernard
Published: April 2009

APPOINTMENT OF a new director, initiation of several new programs and continuing expansion were characteristic of the American Institute of Physics in 1966. The annual report, just issued by Ralph A. Sawyer, who was acting director during most of 1966, also calls attention to the appointment of several persons to key positions in the organization. While most activities of the institute continued as they have been conducted in past years, a major reorganization occurred in information and documentation.
Pion-Proton Scattering Verifies Forward Dispersion Relations
Authors: Lubkin Gloria B.
Published: April 2009

A year-long on-line computer experiment at the Brookhaven AGS has verified the dispersion relations for forward elastic scattering at energies as high as 29 GeV. The experiment, done by S. J. Lindenbaum, Satoshi Ozaki, Kenneth J. Foley, Roger S. Jones, William A. Love, Edward Platmer, C. A. Quarles and Erich Willen, measured the π+−p and π−−p elastic scattering cross sections from 8 to 26 GeV at 1 to 30 milliradians. (Results were reported at the Coral Gables Conference on Symmetry Principles at High Energies late in January and at the New York APS meeting.) The experiment, according to Lindenbaum, gives one a quantitative crystal ball that looks all the way to infinity.
LRL Plans Synchrotron and Storage Ring for Heavy Ions
Authors: Holbrow Charles H.
Published: April 2009

The AEC has provided $4 million for studies of a multipurpose accelerator to produce beams of ions of any element from hydrogen to uranium with a wide range of energies. It is being planned at the Lawrence Radiation Laboratory in Berkeley. Its designers, Albert Ghiorso, Robert M. Main and Bob H. Smith, call it the “Omnitron” because of its versatility; the accelerator is intended to serve biophysicists and nuclear physicists interested in heavy-ion reactions or medium-energy physics research with light ions. Protons will have a maximum energy of 1.5 GeV, and heavier ions will be able to reach maximum energies from 300 MeV/nucleon to 500 MeV/nucleon; beam intensities will range from 1011 to 1013 particles/sec depending upon the kind of ion accelerated.
Phimsy
Authors: Ellis R. Hobart
Published: April 2009

I talk with Gloria Lubkin; Thermodynamics in song; The editorial evaluators
Ernst Mach as teacher and thinker
Authors: Blüh Otto
Published: April 2009

THE YEAR OF Ernst Mach's hundredth birthday, 1938, was the first occasion for commemorating his work. At that time the difficult political situation in Central Europe made any such event unfeasible. The members of the so-called “Vienna School” of neopositivism, who at their beginning had assumed the name of “Ernst Mach Society,” had dispersed, and in Prague, where a program of lectures on Mach had been prepared, the celebrations had to be curtailed because of unrest in the spring of 1938. Spring of 1966 was the next opportunity for remembering Mach and his work, on the 50th anniversary of his death in 1916. In fact, the “Ernst-Mach-Institute” in Freiburg im Breisgau arranged an international conference on Mach, and last December the American Association for the Advancement of Science, with its Ernst Mach Symposium, also shared in honoring Mach's personality and work.
Many-Body Effects Found In Solid-State Plasma
Authors: Lubkin Gloria B.
Published: April 2009

Spin waves, which are collective periodic variations of the magnetization vector, have been found in both sodium and potassium. This is the first observation of genuine many-body effects in a solid-state plasma, and it confirms the collective Fermi-liquid model first proposed by Lev Landau ten years ago.
Laser applications
Authors: Maiman Theodore H.
Published: April 2009

WHEN THE LASER was developed in mid-1960, it was hailed—primarily by science writers—as the solution to problems ranging from such commonplaces as television transmission and metal drilling to science-fiction tools like the instant death ray. This effort to glamorize the laser and portray it in terms of commercial and industrial application continues to occupy the bulk of the attention focused on it today. Such publicity is somewhat misleading, but the laser's role as a scientific tool is now well established.
Magnetic spectrographs
Authors: Enge Harald A.
Published: April 2009

MAGNETS HAVE BEEN USED as experimental aids in nuclear physics since the earliest days of radioactivity studies. From the first crude devices used 60 years ago to the modern charged-particle spectrographs used today, there has been a tremendous increase in complexity and utility of these instruments and, of course, an accompanying increase in weight and cost—sometimes by as much as a factor of 105.
Soviet low-temperature physics
Authors: Hammel Edward F.
Published: April 2009

THE SOVIET ACADEMIES of science put great emphasis on low-temperature physics and strongly support a vigorous program of both basic and applied research in this field. For example, the new Kharkov laboratory is undoubtedly the largest in the world devoted exclusively to low-temperature investigations. These were some of the impressions that some of my low-temperature colleagues and I gathered when, after the Tenth International Conference on Low Temperature Physics, we toured laboratories in Kharkov, Tbilisi and Leningrad.
Climate control
Authors: Roberts Walter Orr
Published: April 2009

LIFE IN A TECHNICALLY advanced society like ours is increasingly dependent on an understanding of atmospheric behavior. Food, travel, recreation, commerce—these and many other major aspects of the daily duties of men are strongly affected by the vicissitudes of weather and climate. Even the subtle joys of life turn upon wind and storm, as with the smell of rain in a wheat field, the flowers on a mountain hillside, the beauty of a sunset or even the opportunity to see a sunset at all.
Short, Intense Laser Pulse Makes Crystal Transparent
Authors: Lubkin Gloria B.
Published: April 2009

Although ruby is almost opaque to certain light frequencies, it can be made transparent to one of those frequencies according to Erwin Hahn and Samuel McCall of the University of California, Berkeley. The trick is to apply a sharp pulse of intense, coherent light at a frequency that matches a resonant transition in ruby. If the ruby is cold enough the pulse will be transmitted and the light can be slowed down to as little as 1% of its usual velocity. This self-induced transparency, predicted theoretically a year and a half ago by Hahn and McCall, was recently reported by them (Phys. Rev. Letters 18, 908).
Phimsy
Authors: Ellis R. Hobart
Published: April 2009

Galileo, old and new; Analysis for Wall Street…; …and playing the horses; Cartoons and smoke photos.
The search for element 102
Authors: Ghiorso Albert , Sikkeland Torbjorn
Published: April 2009

SYNTHESIS AND IDENTIFICATION of chemical elements with atomic numbers greater than 100 (fermium) have been accomplished with extremely small amounts, literally on a one-atom-at-a-time basis. At the present time these elements can only be formed with accelerated ions, ranging from neon to helium, that bombard targets from uranium to einsteinium. Because of their minuscule transmutation cross sections, such experiments are extremely difficult to perform, and often the results are subject to error and uncertainty of interpretation.
Optical methods for the study of radio-frequency resonances
Authors: Kastler Alfred
Published: April 2009

D URING MY FIRST YEAR as a student at the Ecole Normale Supérieure in Paris, our professor, Eugene Bloch, introduced us to quantum physics, which was seldom taught in France at that time. Like him, I was from Alsace and spoke German. He strongly advised me to read Arnold Sommerfeld's excellent book Atombau und Spektrallinien. When reading this book, I was particularly interested in the application of the principle of conservation of angular momentum in interactions between electromagnetic radiation and matter—an application that guided A. Rubinowicz to the interpretation of the selection rules for the angular momentum quantum number and for polarization in the Zeeman effect. On the assumption of light quanta, this principle led to attributing an angular momentum to the photons +h/2π or −h/2π, according to whether the light was circularly polarized to the right (σ+) or to the left (σ−), natural light being a mixture of the two types of photon.
APS–AAPT meet in Chicago
Authors: Carr Bruce C.
Published: April 2009

The highlights of this year's joint annual meeting of The American Physical Society and the American Association of Physics Teachers will be a memorial session for John C. Slater, discussions on trends toward applied physics in physics education and a special symposium on the applications of physics in agriculture. The Societies have chosen the windy city of Chicago as the location for the meeting, which will be held 7–10 February.
Geothermal energy development
Authors: Rowley John C.
Published: April 2009

The interior of the Earth represents an enormous reservoir of energy. Most of it, with the exception of the relatively thin surface-crust material, is at a temperature either close to, or above, the melting-point range for the rock and metallic alloys that make up the mantle and core. Yet this great energy reservoir is not at present a generally useful resource, being currently tapped only in a few small areas where surface conditions permit an economic yield. What are the problems limiting the development of geothermal energy to its full potential?
Recent advances in neutron physics
Authors: Feshbach Herman , Sheldon Eric
Published: April 2009

“At twilight on the sixth day of Creation, so say the Hebrew commentators to the Old Testament, God made for man a number of tools that give him also the gift of creation. If the commentators were alive today, they would write God made the neutron.” In these dramatic words the late mathematician and science historian Jacob Bronowski conveyed the importance of the neutron to modern man. Indeed, nuclear physics as we know it may be said to owe its origins to the 1932 discovery of the neutron. We are coming increasingly to appreciate the enormous significance and variety that neutron physics displays throughout the entire realm of the physical sciences and beyond, into such developing areas as therapy, bioanalysis, materials research and astronomy. To survey in any comprehensive fashion the advances achieved over the past decade alone would carry us far beyond the scope of an article such as this. We therefore will touch only upon some of the salient features on which fresh light is being shed and discuss some of the fields in which neutron physics is being called upon to play a prominent part.
The roots of solid-state research at Bell Labs
Authors: Hoddeson Lillian Hartmann
Published: April 2009

Solid-state physics has experienced a dramatic growth in the last four decades; whereas in the 1920's the term “solid-state physics” was not yet in use, this is now the single most populated sub-field of physics. Much of this growth has taken place in industry, so that today a small number of industrial laboratories are producing a substantial fraction of contributions in the field.
Electron microscopy of atoms in crystals
Authors: Cowley John M. , Iijima Sumio
Published: April 2009

From its beginnings the field of electron microscopy has sought, as its ultimate aim, the ability to study the structure of matter by imaging the individual atoms that compose it. The resolution necessary to attain this goal is obtainable in principle, because the electron wavelengths of the beams normally used are less than 0.1 Å, What has kept this goal from realization are practical difficulties in the design and construction of electron microscopes. These difficulties have now been overcome to the extent that resolutions of 2–3 Å, close to the interatomic distances in some solids, have been achieved.
March Meeting in San Diego
Authors: Carr Bruce C.
Published: April 2009

Always eager to gather in warmer climates after the annual meeting, The American Physical Society has selected San Diego as the location for its second general meeting of the year. The meeting will be held 21–24 March and the headquarters hotel is the Town and Country Convention Center and Hotel.
The case of the vanishing superconductivity
Authors: Lubkin Gloria B.
Published: April 2009

A ternary superconductor, ErRh4B4, does an astonishing thing as its temperature is reduced: Although at 8.6 K it becomes superconducting, as the temperature is reduced further, to 0.9 K, the superconductivity disappears. This discovery was scheduled to be reported by Bernd T. Matthias (University of California, La Jolla and Bell Labs) in a postdeadline paper at the March meeting of The American Physical Society in San Diego. Matthias says that this is the first time an ordered crystal has lost its superconductivity as the temperature is lowered.
Scyllac expires: And now there are two
Authors: Lubkin Gloria B.
Published: April 2009

Last year ERDA gave Los Alamos Scientific Laboratory a deadline of September 1977 to demonstrate stabilization of plasma in Scyllac, a circular theta-pinch device that had been one of the three major components of the magnetic-fusion program (PHYSICS TODAY, July 1976, page 17). Now ERDA and Los Alamos have decided to terminate operation of Scyllac between 1 July and 30 September.
The future of unified gauge theories
Authors: Weinberg Steven
Published: April 2009

Unified gauge theories of elementary-particle interactions have had an exciting start. In this article, I want to try to look a little way into their future.
Survey satellite to map high-energy sources
Authors: Bennett Floyd C.
Published: April 2009

The first in a series of High Energy Astronomy Observatory satellites, HEAO-A, will be inserted in June into a low circular orbit about the Earth from NASA's Kennedy Space Center. The new satellite will spend its six-month mission lifetime surveying and mapping x-ray sources throughout the celestial sphere, and also measuring low-energy gamma-ray fluxes; its purpose is to amass experimental data related to radio galaxies, neutron stars, pulsars, quasars, stellar explosions and supernovas. The HEAO-A carries a payload of four experiments. In 1978 and 1979 NASA expects to launch other High Energy Astronomy Observatories to complete the $237-million, three-mission HEAO program.
High-resolution spectroscopy of atoms and molecules
Authors: Hänsch Theodor W.
Published: April 2009

Lasers are rejuvenating, even revolutionizing, the field of spectroscopy of atoms and molecules. Compared with the light of conventional sources, laser light is more—sometimes dramatically more—powerful, directional, spectrally pure and coherent. Laser light can be generated in extremely short pulses. Furthermore, tunable lasers can operate at wavelengths at which intense conventional sources such as spectral lamps simply have not been available. Lasers thus can enormously enhance the sensitivity and application range of classical spectroscopic methods, such as absorption spectroscopy, fluorescence spectroscopy and Raman spectroscopy.
Coherent Raman spectroscopy
Authors: Levenson Marc D.
Published: April 2009

In 1928 Chandrasekhara Raman reported a process in which a material would simultaneously absorb one photon and emit another. The energies of the two photons differed by an amount corresponding to the energy difference between two quantum-mechanical levels of the medium. Raman scattering, as the phenomenon came to be known, provided a tool for the spectroscopic investigation of energy levels not accessible by the usual absorption and emission techniques. For the first thirty-five years Raman scattering was a laborious and exotic technique, important more for the quantum-mechanical principles it illustrated than for its practical applications.
Coherent optical transients
Authors: Brewer Richard G.
Published: April 2009

The dynamics of nuclear spins in atomic and molecular environments have been examined in exquisite detail over the past 27 years by the methods of pulsed nuclear magnetic resonance. The early discovery of the spin echo by Erwin Hahn and the transient nutation effect by Henry Torrey initiated the field by introducing coherent transient phenomena to radio-frequency spectroscopy. An entire class of coherent spin transients could be observed by a simple variation of the rf pulse sequence, and from the decay characteristics the various spin-dephasing mechanisms could be examined separately. In short, these methods allowed decomposition of the spin-transition linewidth into its broadening components, and also offered new and versatile ways for performing high-resolution rf spectroscopy.
The cosmological constant and cosmological change
Authors: Tinsley Beatrice M.
Published: April 2009

Is the Universe of infinite extent, or is it a finite system? Will it expand forever, or will it reach some maximum size before turning and collapsing upon itself like an inverse Big Bang? Just a few years ago, models of the conventional Friedman types were showing consistent, albeit tentative, evidence for an open, ever-expanding Universe. Since then, further data and theory have inevitably conspired to blur the appealing simplicity of that picture. In this article I will show how the Friedman models fare in the light of new developments—particularly the recognition of a whole new class of evolutionary corrections to the properties of distant galaxies (see figure 1), and a proposed reinstatement of Einstein's disinherited cosmological constant. We shall see that the basic questions, posed above, are still unanswered.
High-conductivity graphite compounds
Authors: Levi Barbara G.
Published: April 2009

The measurement of high electrical conductivity in a synthetic metal at room temperature was one of many observations discussed at the Conference on Intercalated Compounds of Graphite held in La Napoule, France last month. Although these compounds have been studied—largely by chemists—for some 40 years, physicists have recently taken a renewed interest in them because they offer the potential for technological applications as well as the opportunity to explore electronic and other properties of materials of variable dimensionality.
What the exploration of Mars tells us about Earth
Authors: Rasool S. Ichtiaque , Hunten Donald M. , Kaula William M.
Published: April 2009

The success of the Viking missions has a special significance for the student of planetary evolution who considers such questions as: How did the atmosphere and oceans originate on Earth? What circumstances created the benign environments at the surface of Earth so that the first synthesis of living organisms could take place three to four billion years ago? What do continental drift, earthquakes, and other surface tectonic and volcanic activity indicate about the interior and its evolution? What stimulates a long-term climatic change—such as an ice age? It is interesting that the experiments being performed by Viking touch on each of these questions and that data from Mars will contribute significantly to scientific progress in these fields. In essence we are trying to understand why Earth and Mars evolved so differently (see figure 1).
Large-scale applications of superconductivity
Authors: Schwartz Brian B. , Foner Simon
Published: April 2009

Ever since its discovery by Kamerlingh Onnes in 1911, superconductivity has contained the promise of important applications. The ability of superconductors to carry current without resistance was expected to revolutionize the field of electrical engineering. The fulfillment of this promise, however, was deferred for half a century; it is only since the mid 1960's that there has been much progress in applied superconductivity. Superconductivity, with its ability to generate an intense, large-volume magnetic field economically, can now offer alternatives in the fields of energy generation, storage and distribution as well as in transportation. Some prototype quasi-commercial devices are already in use, and approximately 30 million dollars are being spent annually to develop this technology further.
Space vehicles could be propelled by remote lasers
Authors: Lubkin Gloria B.
Published: April 2009

Interest is apparently growing in using a high-energy laser to power a vehicle that is a considerable distance away from the laser. The laser can be located on the ground and used to propel a spacecraft into orbit or even to power an airplane. Alternatively the laser can be located in orbit itself and used to propel a spacecraft into higher orbit.
Sandia and Kurchatov groups claim electron-beam fusion
Authors: Lubkin Gloria B.
Published: April 2009

Experimenters at Sandia Laboratories in Albuquerque, N.M. believe they have produced about a million neutrons per pulse from thermonuclear fusion induced by bombarding a pellet with an electron beam. Last year Leonid I. Rudakov and his collaborators at the Kurchatov Institute in Moscow had reported the production of similar amounts of fusion neutrons produced by electron beams. However, Gerold Yonas, who heads the Sandia Fusion Research Department, believes that his group is the first to use the so-called “magnetic thermal insulation” principle, which allows relatively low power to be used in the electron beams. The electron-beam yields are about a factor of 1000 less than that achieved thus far with lasers.
Helping shape legislative policy
Authors: Hoffman Allan , Moss Thomas , Whiteside Haven
Published: April 2009

We came to Congress in the plateau of the energy crisis. The initial crunch of the oil embargo, with its resulting gasoline lines, was already past by the time we became APS Congressional Fellows, but Project Independence was still very much on people's lips. Energy was only one of many subjects the Congress addressed during our year on Capitol Hill, 1974–75, but it was one of the most important ones and one that is of continuing interest to physicists and the community at large.
Tests show CO2 laser is suitable for fusion
Authors: Lubkin Gloria B.
Published: April 2009

Two kinds of lasers are widely used for laser-fusion research, the neodymium-glass laser with 1.06-micron output and the carbon-dioxide laser with 10.6 micron output. It has been a widely held belief that the neodymium-glass laser was far superior for compression of the pellet because of its shorter wavelength. However, recent results at Los Alamos, which were reported at the Conference on Laser Engineering and Applications held in Washington in June, have called this belief into question. The Los Alamos group has compared results with the two kinds of lasers and finds striking similarities despite the factor of ten difference in wavelength. The report was made by Damon Giovanielli, Dale Henderson, Gene McCall and Roger Perkins.
Upsilon particles at 9.4 and 10 GeV suggest new quark
Authors: Lubkin Gloria B.
Published: April 2009

Possible evidence for a new kind of quark has been reported by a group working at Fermilab. The team of experimenters from Columbia University, Fermilab and the State University of New York at Stony Brook observed a dimuon resonance, which they called upsilon, Υ, at 9.4 GeV, by far the most massive resonance ever found. They reported their results at the European Physical Society Particle-Physics Conference held in Budapest in July. Since then the group reported evidence for Υ′ at 10.0 GeV and preliminary indications for a third resonance at about 10.4 GeV. Both upsilon and upsilon prime have widths less than or equal to 200 MeV. These latest results were announced at the International Symposium on Lepton–Photon Interactions held in Hamburg late in August.
Analyzing hydrogen with nuclear reactions
Authors: Picraux Samuel T.
Published: April 2009

There are many ways in which hydrogen plays an important role in today's materials problems. Our newly developed ability to detect and probe sensitively and quantitatively for hydrogen has provided valuable new insight into many of these problems. By means of nuclear-reaction techniques we can develop depth profiles of the hydrogen, deuterium and tritium concentration in various materials; these techniques have already been of practical assistance in several areas of technology, and promise to be helpful in others as well (see box on page 45). Here we shall describe rather briefly the types of nuclear-reaction techniques now used to probe for hydrogen. Then we shall concentrate on the way these techniques have been applied to studies of hydrogen isotopes in various materials, making particular note of the uses of implantation for these studies and the effect of changing the implanted-hydrogen concentration on the observed properties of the bulk materials.
Vacuum Society meets in Boston
Authors: Carr Bruce C.
Published: April 2009

Boston is the site for the 24th National Vacuum Symposium of the American Vacuum Society, which will be held 8–11 November at the Sheraton-Boston Hotel. A technical exhibit will be presented in the John B. Hynes Civic Auditorium, which is adjacent to the hotel. These symposium facilities are both part of the Prudential Center complex, centrally located in downtown Boston on Boylston Street.
Detectors for lightwave communication
Authors: Melchior Hans
Published: April 2009

Telecommunication with light waves today stands at the threshold of widespread use.
Germanium gamma-ray detectors
Authors: Pehl Richard H.
Published: April 2009

Semiconductor gamma-ray detectors consist essentially of a piece of solid material in which electrons and holes are produced when a gamma ray is absorbed. These electrons and holes are then collected by an electric field in the material to provide an electric signal that is a direct measure of the energy of the gamma ray. This simple statement implies detector-material characteristics that are by no means easy to achieve, and much of this article will be concerned with these characteristics.
Observation of optical bistability confirms prediction
Authors: Leuchtag H. Richard
Published: April 2009

An effect predicted in 1969 has been observed experimentally: An intense beam of light can cause an optical medium to pass from one state to another, opaque to transparent. In a complete cycle (opaque–transparent–opaque), the medium exhibits hysteresis.
Physics of textiles
Authors: Treloar L. R. G.
Published: April 2009

While the basic processes of spinning and weaving were developed empirically, the problems and processes of the textile industry have in the last 25 years been the subject of intense scientific activity. The stimulus to this activity has arisen mainly from the impact of the newer polymeric fibers, which have introduced possibilities of improved properties and radically different methods of production and processing. In place of the very small number of fibers supplied by nature, we are now able to select from a great variety of materials, differing widely in both chemical and physical properties, to meet any particular demands. Moreover, these new materials are not limited to textile applications, but are in many cases available also in the form of films for packaging, or in bulk for engineering or other uses. Their study has thus become a branch of the science of polymeric materials, which is one of the most lively fields of scientific activity at the present time.
Errata
Authors: Gorter C. J.
Published: April 2009

Thank you for the way my talk on “Bad Luck” was presented in the January issue. Unfortunately I myself made a few errors in the references, and since those are of some importance in a paper of somewhat historical nature, I hope you will publish a correction:

On page 77, column 1, line 7, read “the expected effect4a.”

On page 77, column 1, line 14, read “sunlight4b.”

Change the references to read as follows:

4a. C. J. Gorter, Leiden Comm. 247a, Physica 3, 995 (1936).

4b. C. J. Gorter, Physica 1, 199 (1934).

5. C. J. Gorter, Arch. Teyler 7, 378 (1933); C. J. Gorter, H. B. G. Casimir, Physica 1, 306 (1934); Phys. Z. 35, 963 (1934).

6. A. D. Fokker, C. J. Gorter, Z. Phys. 77, 166 (1932).
Erratum
Authors: Hutchins Carleen Maley
Published: April 2009

An editor's error that I did not catch caused the omission of an important name from the list of Catgut acousticians that appeared with my February article, “Founding a Family of Fiddles.” Sterling Hunkins should have been listed among the cellists.
Catastrophe map and the role of individual resonances in C2H2 bending dynamics
Authors: Tyng Vivian , Kellman Michael E.
Published: April 2009

A catastrophe map analysis is presented of the birth of new modes in bifurcations of the normal modes of the acetylene pure bending system using a spectroscopic fitting Hamiltonian that is nonseparable with multiple resonances. The map splits into two independent maps for subspaces defined by the resonance frequency conditions. Nonetheless, both resonance couplings act on each of the resonance subspaces, since the system is nonseparable. With this generalized notion of independent resonances, the map accounts for partial resemblances to single resonance models but maintains the full complexity inherent in the nonseparable Hamiltonian. This suggests a way to extend both the generalized Fermi resonance and the catastrophe map analysis to systems with higher degrees of freedom.
Of higher symmetries
Authors: Polkinghorne J. C.
Published: April 2009

During the past year the in-trays of elementaryparticle physicists have been brightened by a new type of preprint cover, the cool blue and white of the International Center for Theoretical Physics at Trieste. The preprints inside have been remarkable for their number, their interest, and the diversity both of their subjects and the home countries of their authors. A truly international institute, drawing postdoctoral workers from every continent, has come into being and has enjoyed a remarkable first year of fruitful activity. This activity reached an appropriate climax in the Seminar on High-Energy Physics and Elementary Particles, held during the months of May and June, 1965, just three years after the first such seminar, held in Trieste in 1962, under the auspices of the International Atomic Energy Agency. The 160 participants came from 29 different countries and the two-month seminar provided a unique and valuable opportunity for survey in depth and continued discussion of all the most important aspects of the subject. Such a period of sustained communal activity provides an altogether different experience from the fleeting contacts possible at conventional short conferences. It constitutes an opportunity for the physicist from a developing country to make lasting contacts with workers from all over the world. However, it is equally welcome to all physicists since the complexities of modern problems demand a time scale of weeks rather than days for their discussion.
Frequency control: Report on the 19th annual symposium…
Authors: Ballato A. D. , Andresen H. G.
Published: April 2009

Specialists in frequency control are improving their crystal vibrators and atomic frequency standards. Toward better crystal devices, they are making filter crystals that operate above 30 Mc/sec; with better mathematical analysis of vibration modes to help, they are using electrode-thickness tuning and crystal shaping to improve crystal response; they are using sound waves and x rays to investigate vibration-mode patterns. Some are seeking new materials to replace quartz, especially endowed by nature to function as a frequency standard. Others have used quartz in a new way to make a new kind of delay line. Toward better atomic frequency standards, they are improving both stability and accuracy. All-solid-state versions are making rubidium gas-cell standards and cesium-beam standards more useful. Other improvements in atomic devices include better circuits for hydrogenbeam tubes, narrower reference lines, and better frequency stabilities, both long- and short-term.
Sound reflections in and under oceans
Authors: Hersey J. B.
Published: April 2009

Modern oceanography is founded on the curiosity and interest of the naturalist with a bent for things marine who, in pursuing understanding of plants and animals of the oceans, has appreciated the need for comparable understanding of their physical and chemical environment. It is also founded on the interest of the physicist who from time to time has been called in to help provide for a human need: to sound ocean depths for laying cables, to make more reliable fog signals, or to avoid icebergs or deal with submarines. Some of the latter have become interested in the oceans or in the physics of the earth beneath for their own sake. No matter what their individual background, main physicists have found fascination in the science of the ocean.
All the red-legged partridges …or… 99.5% retrieval of scientific information
Authors: Way K.
Published: April 2009

The word “retrieve” means “to call to mind again, to find again” or, in hunting terms (obsolete), “to discover again game once sprung, to flush partridges a second time”. Perhaps the ancient usage with respect to birds is the one which gives the clearest idea of the modern meaning to documentalists. “Retrieval” has come to signify the flushing again of such beautiful partridges as journals, books, reports which have found obscure resting places in the dense forests of modern libraries. But a new concept has been added, namely that in each operation the partridges found again should be of a specific kind. “99.5 percent retrieval” now means that if there are 1000 red-legged partridges in the forest, 995 of these can be sprung again at will
Robert R. Davis and Physics Today
Authors: Hutchisson Elmer , Brode Wallace R. , Crane H. Richard , Harris Cyril M. , Havens W. W. , Lee E. H. , Neher H. V. , Routly Paul M. , Slack Lewis , Wood Elizabeth A.
Published: April 2009

This is the last issue for which Robert R. Davis serves as editor of Physics Today. This factual statement says much, but leaves unsaid a great deal more. Bob took the helm of PT in November 1950 during very unsettled times. There was reason to ask, “Could Physics Today survive?” It was slim in size. A few physicists resented openly the action of the American Institute of Physics in initiating a physics journal which they thought must necessarily be beneath their dignity to read. Financial difficulties intensified their misgivings. Advertising was slow in coming, experiments in obtaining subscription income were not always successful, and the wolf was often at the door. Yet the AIP officers and Governing Board had staunch faith. They knew that if the AIP were to be more than a paper organization, some medium of communication among all physicists had to be kept alive.
Report from Chulham… 2. Plasma theory
Authors: Frieman Edward A.
Published: April 2009

As an appendix to Professor Spitzer's survey of the experimental papers presented at the Culham meeting, we here give a short survey of the theoretical papers with the intent of illustrating the present thinking rather than very explicit or detailed results.
Felix Bloch: A brief professional biography
Authors: Schiff L. I. , Hofstadter R.
Published: April 2009

October 23, 1965, the sixtieth birthday of Felix Bloch, has marked an appropriate occasion for review of his accomplishments as one of the great physicists of this generation.
Einstein and some civilized discontents
Authors: Klein Martin J.
Published: April 2009

The French novelist Stendhal began his most brilliant novel with this sentence: “On May 15, 1796, General Bonaparte made his entrance into Milan at the head of that youthful army which had just crossed the bridge of Lodi, and taught the world that after so many centuries Caesar and Alexander had a successor.” In its military context, the quotation is irrelevant here, but it can be paraphrased a bit: almost exactly a century later Milan saw the arrival of another young foreigner who would soon teach the world that after so many centuries Galileo and Newton had a successor. It would, however, have taken superhuman insight to recognize the future intellectual conqueror in the boy of fifteen who had just crossed the Alps from Munich. For this boy, Albert Einstein, whose name was to become a symbol for profound scientific insight, had left Munich as what we would now call a high-school dropout.
Hurdling the language barrier
Authors: Beyer Robert T.
Published: April 2009

When a scientist sets to work in his laboratory today, anywhere in the world, he can be assured that groups of other scientists in a dozen or more places, are engaged in work on the same problem, or on a closely related one. It would be of help for this scientist to know what the others had already done, what they were attempting, and what might be tried by them in the future. How does he go about finding this information?
Society of Rheology
Authors: Prager Stephen
Published: April 2009

Over the past five years the membership of the Society of Rheology has held reasonably steady at around 650, and the attendance at the annual fall meeting has also remained approximately constant at about one-third of that number. In contrast to these figures, the number of papers presented has almost doubled. At the 35th Annual Meeting of the Society, which was held October 26–28, 1964, at the Mellon Institute in Pittsburgh, Pa., there were 62 papers on the program, necessitating double and evening sessions. As much as possible, the sessions were organized along topical lines: melt flow, thermodynamics and constitutive relations, dynamic viscosity, network polymers, viscosity-structure relations, hydrodynamics of viscoelastic flow, and experimental nonlinear viscoelastic flow. In addition, there were three sessions of general papers, plus a special one-day session on the physics and mechanics of random media.
Semiconductor lasers
Authors: Rediker Robert H.
Published: April 2009

Since the announcement of the GaAs diode laser in November 1962, laser action has been achieved in diodes of a variety of III–V and IV–VI direct-gap semiconductors. The wavelength of the emitted radiation varies over the range from 6300 Å for the III–V mixed semiconductor Ga(AsxP1−x) to 85 000 Å for the IV–VI semiconductor PbSe. The semiconductor diode laser has the advantages that its size is small, that it converts electric power directly into coherent light, and that its output can be modulated by simply modulating the diode current. Figure 1 shows an artist's sketch of a GaAs diode laser in a pill-type package. Such a laser, when operated between 4° and 20°K, has emitted up to 6 W of continuous coherent radiation at close to fifty percent power efficiency, and the radiation has been modulated at frequencies up to 11 Gc. At room temperature such a laser can be used on a pulse basis and 20 W of coherent radiation can be emitted in 50 nsec pulses. When operated continuously at currents not too high above threshold, GaAs lasers can operate stably in one mode of the Fabry-Perot cavity formed by the cleaved face, shown in Fig. 1, and the parallel face on the opposite end of the laser. The width of such a cavity mode has been measured to be less than 50 Mc/sec or less than 1.5 parts in 107 of the output frequency.
Nuclear physics: A report on the Paris conference
Authors: Danos Michael
Published: April 2009

Being an affair organized on the occasion of the thirtieth anniversary of the discovery of artificial radioactivity by Frederick and Irene Joliot-Curie, the Paris Conference on Nuclear Physics had, and was supposed to have, aspects of both a conference and of a show. Several factors contributed to its eminent success as a conference. In chronological order of impact, the first of these was the elevated spirits induced, at least for non-Parisians, just by the magic of Paris. The second was the excellence of the facilities and of the organization. The third was the high quality of the papers and, in general, of their presentation. The last, but in the end the most important, factor was the impression of the vitality, one even may say rebirth, of nuclear physics as a field.
Theoretical physics
Authors: Woods E. J.
Published: April 2009

The third annual Eastern United States Theoretical Physics Conference was held at the University of Maryland in College Park on October 30 and 31, 1964. The first and second conferences were held at the University of Virginia and the University of North Carolina, respectively. In two years the attendance more than doubled, with 269 participants at the most recent meeting. This may be a crude measure of the scientific value of such a conference, but it does seem to be an established success.
Charge and spin density
Authors: Weiss R. J.
Published: April 2009

The above excerpt might be taken from specifications for an Army tank in the year 2064 since high-speed computers may then be capable of calculating all pertinent observables (strength, hardness, thermal conductivity, etc.) from the wave functions. However, projected military requirements a hundred years hence had little to do with the Army's sponsorship of the Sagamore conference on charge and spin density (Aug. 17–21, 1964), which resulted rather from an active interest of the research group of the US Army Materials Research Agency at Watertown, Mass., in the measurement and calculation of charge and spin density.
Ethical problems of scientists—a summary
Authors: Cranberg Lawrence
Published: April 2009

The relationship of ethics to science has long been discussed as a theoretical problem by a few specialists. In recent years ethical problems associated with activity in science have acquired for many scientists a major importance on the practical level, often without having been tagged explicitly as “ethical”, or, in many cases, without having been brought above the threshold of awareness as problems worthy of serious attention. Ten such problems are identified below.
Low-energy electron-atom and electron-molecule scattering theory circa 1964
Authors: Gerjuoy E.
Published: April 2009

Let me begin with the remark that, to avoid continual reiteration of an awkward phrase, I shall simply say “electron scattering” where it is obvious that I am referring to electron-atom and/or electron-molecule collisions, which collisions may be elastic or inelastic. Progress in electron-scattering theory has been reviewed on numerous occasions in recent years, by various authors. Thus, there is not much point in trying to re-review in detail here the whole subject of electron scattering, especially since I couldn't possibly do it within the pages of this entire issue of Physics Today. Instead, I shall confine my attention largely to topics wherein what has been happening within the past two years or so seems important. By important, I mean that—to me at least—these happenings suggest modifications of apparently established points of view. Even with this very severe restriction on the subjects I intend to discuss, I really can't do justice to the available material in an article of this length. A reasonable idea of the feverish present activity in the field of electron scattering, as well as a notion of the breadth of topics falling under this general subject heading, can be obtained from thumbing through the Proceedings of the Third International Conference on the Physics of Electronic and Atomic Collisions.
The role of pure science in European civilisation
Authors: Powell C. F.
Published: April 2009

The subject on which I am to address you raises novel problems of great public interest and importance. We are surely all very conscious of the fact that the headlong advance of science, and the technological developments which it has called into being, have profoundly modified our whole civilization and the process is manifestly continuing. Science is an indispensable and rapidly growing element in our culture.