bluuebunny/crossref_metadata_2025 huggingface dataset:
Entropy and Indistinguishability
Authors: Hestenes David
Published: August 2005

It is argued that the principle of indistinguishability of identical particles is a necessary condition for consistency between experimental and statistical descriptions of a many-particle system. Therefore, it is not a special feature of quantum theory, and its use is perfectly justified in classical statistical mechanics.
Kohlrausch Heat Conductivity Apparatus for Intermediate or Advanced Laboratory
Authors: Jensen H. G.
Published: August 2005

A student experiment in measuring heat conductivity according to Kohlrausch's method is described. Theory, apparatus design, and experimental procedure are outlined. Results for copper are consistent to within 2%. Measurements may be accomplished in one or two laboratory sessions (6–8 h).
The Inverted Pendulum
Authors: Kalmus Henry P.
Published: August 2005

An analysis of the operating conditions of an inverted pendulum is presented based on the assumption that instead of sinusoidal excitation a series of short impulses is applied to the point of suspension. It is believed that this method leads to a more intuitive understanding of the phenomenon.
Distribution Theory of Vector Fields
Authors: Gagnon Ralph J.
Published: August 2005

A review of the basic ideas of Laurent Schwartz's theory of distributions is given. Some fundamental distributions are defined, such as the Heaviside unit-step distribution, Coulomb's 1/r distribution, and the various Dirac distributions which replace a volume integral with surface and line integrals, and evaluation at a point. The main purpose of the paper is to develop a systematic procedure for deriving identity relationships between the important vector distributions. Relationships between the Heaviside, Coulomb, and Dirac distributions are derived, and the results are organized and displayed in an appendix. Several applications are given in order to demonstrate the usefulness of these results. Included are discussions of the electric dipole, the Amperian current magnet, the electromagnetic jump conditions at a moving boundary, and the field distributions from a moving charge.
A Variational Principle for Nonholonomic Systems
Authors: Saletan Eugene J. , Cromer A. H.
Published: August 2005

The equations of motion for a Lagrangian system with velocity-dependent constraints, which cannot be obtained from the variational principle of Lagrange, are shown to follow from a different variational procedure in which the comparison paths do not satisfy the constraint conditions. The new variational problem reduces to the Lagrange problem when the constraints are holonomic. In presenting the variational problem a new approach to Lagrange multipliers is introduced.
The Contributions of Felix Bloch and W. V. Houston to the Electron Theory of Metals
Authors: Rorschach H. E.
Published: August 2005

This article is taken from an address given at a conference honoring Felix Bloch at Stanford University, 25–26 October 1968.
The Physics and Physiology of Insect Flight
Authors: Deakin Michael A. B.
Published: August 2005

Considerations of dimensional analysis are used to derive a formula connecting wing-beat frequency with mass and wing area for a flying insect. The formula is used to demonstrate the existence of asynchronous flight muscle.
General Born Diagram and Legendre Transformation
Authors: Cheng Chien-Chung
Published: August 2005

A general Born diagram has been constructed for any Legendre transformation. The general Maxwell equations are derived. Their applications are illustrated for the cases of thermodynamics, fluid dynamics, and classical mechanics.
Geometrical Appearances at Relativistic Speeds
Authors: Scott G. D. , van Driel H. J.
Published: August 2005

Geometrical appearances at relativistic speeds (β = 0.5, 0.9, and 0.995) are illustrated for the following examples: (i) the celestial sphere with a number of constellations, (ii) the surface features of a sphere passing close to an observer, and (iii) a train of rectangular boxes. The figures make clear the nature of the distortions which occur in appearances, indicate the limited significance of the so-called “apparent rotation,” and show the conditions under which the Lorentz contraction can be seen or photographed. Though a sphere remains essentially circular in outline, the apparent cross section may be grossly distorted and under some conditions the outside surface of the sphere appears concave.
Computer-Animated Film of Hydrogen Wave Functions
Authors: Galley S. W.
Published: August 2005

This article describes a computer-animated film loop that depicts the wave functions for the electron in a hydrogen atom.
Charge Redistribution in the Anderson Model
Authors: Sinha Om P.
Published: August 2005

A simplified calculation of the modified electron density away from an impurity in the Anderson model has been given, illustrating the use of the Green's-functions method. This charge redistribution density is found to have the oscillatory behavior of Ruderman-Kittel function with a phase shift which, it is shown, satisfies the Friedel sum rule.
The Josephson Effect and e/h
Authors: Clarke John
Published: August 2005

A Josephson junction, consisting of two superconductors weakly coupled together, is an example of a very simple macroscopic quantum system. When there is a voltage V across the junction, the supercurrents flowing through it oscillate at a frequency given very precisely by the relation v = 2eV/h. The general validity of this formula has been used recently by Parker, Langenberg, Denenstein, and Taylor as the basis for a new determination of the fundamental constant ratio e/h. The new value is 38±10 ppm smaller than the previously accepted value. This result has far-reaching implications concerning the values of the fundamental constants and quantum electrodynamics. This article begins with a simple derivation of the Josephson voltage-frequency relation. Theory suggests that there should be no significant corrections to this equation, a result which is well confirmed by experiment. Various types of junction are then described, together with their applications to the measurement of e/h. The impact of this measurement upon the fundamental constants and quantum electrodynamics is briefly discussed. It seems likely that Josephson junctions will have an important application in comparing and maintaining standards of electromotive force.
Fresnel Diffraction Using a He-Ne Gas Laser
Authors: Moen Allen L. , Vander Meulen David L.
Published: August 2005

An advanced laboratory experiment of Fresnel diffraction is presented. A He-Ne gas laser is used as the source and a wire is used as the opaque diffracting strip. A photograph of the diffraction pattern is compared with the intensity diagram predicted by the Cornu spiral method. Agreement is clear and impressive, although minor differences are detectable.
Frequency Doubling in the X-Band Doppler Shift Experiment
Authors: Taylor K. N. R.
Published: August 2005

An interesting extension to the conventional Doppler shift experiment is described. The basic equipment is similar to other X-band systems and is built around a 4-port directional coupler. By using a vibrating mirror in place of the normal constant velocity reflector, the output from the mixer can be observed to occur at both the expected Doppler frequency and at double this frequency, depending on the position of the mirror. This rather surprising result is discussed in terms of a pseudo-standing-wave model and also in terms of mixing the Doppler shifted frequency with the transmitted frequency.
Reflections on a Wave Packet Approach to Quantum Mechanical Barrier Penetration
Authors: Bramhall Mark H. , Casper Barry M.
Published: August 2005

We consider the time development of a one-dimensional Gaussian wave packet. Noting that the quantum mechanical predictions concerning position and momentum measurements of a free particle described by a Gaussian packet are consistent with the predictions one would make on the basis of a classical “Naive Model,” we investigate whether this model can account for the scattering of a particle by a rectangular barrier. Obtaining numerical solutions of the time dependent Schrödinger equation for a series of packets with varying incident momenta, we find that the Naive Model is inadequate to explain the quantum mechanical transmission. We study the relative speeds of the transmitted and reflected packets, discussing a number of possible interpretations and indicating the quantum mechanical result. Finally, we note that for certain choices of the parameters describing the packet and the barrier, the reflected packet is composed of two distinct humps.
A Rotating Coordinate Frame Visualizer
Authors: Goodman John M. , Chandler David S.
Published: August 2005

An apparatus is described which permits experiments performed on a rotating platform to be projected on a screen as they would appear to an observer in the rotating coordinate frame. The apparatus consists of a specially constructed overhead projector with a variable speed turntable and uses a suitably rotating dove prism to project a nonrotating image. A number of simple experiments which can be done on this apparatus are described. The principal purpose of the equipment is to convey an intuitive understanding of rotating reference frames and especially the centrifugal and coriolis pseudoforces.
Report on the Texas Project in Science Education
Authors: Clark Robert Beck
Published: August 2005

This report summarizes the philosophy and history of a project originated by the author and F. W. de Wette. The primary purpose of the program has been to find and develop methods for utilizing the talent and training of physicists with advanced degrees in the enrichment of precollege science and mathematics education. Various aspects of the program are discussed including the importance of university affiliation, the placement of professional physicists as secondary school physics and mathematics instructors, certification methods, and the development of Regional Science Advisor programs. It is hoped that the initial success of the program will stimulate similar and more imaginative efforts in other areas.
An Experiment on Electron Emission
Authors: Dodd Jack G.
Published: August 2005

A thermionic emission experiment is described in which the cathode temperature is determined from the energy distribution of the emitted electrons. The experiment can be carried out using a commercially available tube and a millimicroammeter of modest performance and so is quite suitable for undergraduate laboratories at the sophomore and junior level.
The Curious Bands of Talbot
Authors: King Allen L. , Davis Randall
Published: August 2005

We call attention to an old phenomenon that can still intrigue students in a contemporary physics course. Talbot's bands are investigated in an undergraduate laboratory project by utilizing commonly available apparatus. Variations of band spacing throughout the visible spectrum are measured. The effects on the pattern of retardance of the thin glass plates in the system and of the width of the grating or prism also are observed. An elementary theory is applied to describe these measurements and observations.
Free-Body Diagrams (a PLATO Lesson)
Authors: Sherwood Bruce Arne
Published: August 2005

A lesson has been written for the PLATO computer-based education system which tutors students in a systematic approach to dynamics problems involving free-body diagrams. The lesson is described in detail and illustrated with photographs of the student's graphical display screen.
Accessible Energy in Quantum Systems
Authors: Walther Adriaan
Published: August 2005

A quantum system in a mixed state can transfer only part of its energy to a quantum system in a pure state, if we require that the final state of the second system is once again pure. We calculate this accessible energy by constructing the optimum unitary operator that connects the initial state of the combined system with its final state. We show that for large systems such as commonly considered in thermodynamics a simple entropy argument suffices but that this method of calculation may yield results that are too large for simpler systems, owing to the constraint that the time development operator must be unitary.
A Course for Graduate Preparation for Teaching
Authors: Stumpf F. B.
Published: August 2005

This course represents an attempt to help prepare graduate students for careers in college teaching in physics. It attempts to increase their awareness of new developments in higher education as well as in physics education. In addition, it gives them information of practical value for their teaching and finally, practice teaching with peer evaluation. It is noted that cooperation with the College of Education was beneficial in carrying out the course.
Floquet's Theorem and Band Theory in One Dimension
Authors: Cottey A. A.
Published: August 2005

Floquet's theorem, and the general qualitative features of the band structure, are described in the one-dimensional case. The discussion includes a little-known unstable state at band edges that is not a Floquet function. This “band edge state” can in certain cases play a role in a thin crystalline layer, analogous to the role of a surface state in a semi-infinite crystal. Some incorrect and misleading statements about Floquet's and Bloch's theorems, which are widespread in expository accounts of the subject, are pointed out.
Additivity of Phase Shifts for Scattering in One Dimension
Authors: Kujawski E.
Published: August 2005

Scattering by two delta-function potentials in one dimension is solved using the “one-dimensional partial wave” analysis developed by Eberly. Despite its simplicity, the above example exhibits a wide range of multiple scattering effects and is quite useful for illustrating some of the difficulties associated with scattering by a many-body system. We use this example to investigate the validity of additivity of phase shifts, which is one of the basic assumptions in Glauber's multiple scattering formalism.
Poincaré's Rendiconti Paper on Relativity. Part I
Authors: Schwartz H. M.
Published: August 2005

“Sur la dynamique de l'électron,” published in 1906 in Rendiconti del Circolo Matematico di Palermo, is Poincaré's principal publication dealing with relativity. It is, among other things, of very considerable historical interest. To make it more readily accessible, the contents of this comprehensive paper will be presented, in a modernized version, in three parts that correspond to the three major topics treated in the paper. The first part, presented here, deals with the principle of relativity and the Lorentz group as well as with the action principle of Maxwell-Lorentz systems.
Acceptability of the Doctor of Arts Degree in Physics
Authors: Price Joseph E.
Published: August 2005

To determine whether or not a person earning a Doctor of Arts degree in physics would be employed by a scholastic institution, in February 1970 a questionnaire was sent to most of the schools in the west that offer courses in physics. The results indicate that a person with a Doctor of Arts would be considered for a position at most junior colleges and at some colleges with BS/BA programs if a position were available.
Invariant Variables under Similarity Transformations
Authors: NiCastro J. R. A. J.
Published: August 2005

Construction of similarity variables is discussed from a geometric perspective that is intended to be a supplementary point of view to the algebraic search for symmetric solutions.
Low-Cost High-Resolution Ebert Spectrographs for a Teaching Laboratory
Authors: Schreiber C. L. , Wong Eugene Y. , Johnston David
Published: August 2005

We have designed, constructed, and tested several Ebertmounted spectrographs that utilize low-cost commercial components and find that 75% or more of the theoretical resolving power was obtained in each case. These instruments are now in use at UCLA in several experiments involving Zeeman effects and hyperfine structures that usually require an expensive Fabry-Perot interferometer or high-resolution spectrograph, and have given excellent results in the undergraduate spectroscopy laboratory course. The 2-m and 212-m instruments are also used in PhD research projects since they are comparable to the commercial equipment available in this department.
The Magnetic Scalar Potential
Authors: Bronzan J. B.
Published: August 2005

We obtain closed expressions for scalar magnetic potentials due to an arbitrary static current density J(x). Simple prescriptions are given for forbidden regions where B ≢ −∇ψ; these forbidden regions make the potential single valued where it can be used. Finally, the complete multipole expansion of the magnetostatic field is derived in a few simple steps.
Light Scattering from Polaritons
Authors: Scott J. F.
Published: August 2005

This paper is tutorial and reviews the experimental studies of inelastic light scattering from polaritons. It comprises one of several lectures delivered by the author at the summer school on light scattering, Northwestern University, July 1970. A complete bibliography is included.
Application of the Theory of Irreducible Tensor Operators to Molecular Hyperfine Structure
Authors: Cook Robert L. , De Lucia Frank C.
Published: August 2005

The theory of irreducible tensor operators is employed to evaluate the matrix elements of the electric quadrupole and magnetic dipole interactions for molecules with several coupling nuclei. Two different coupling schemes are considered, namely the unequal coupling and nearly equal coupling representations. The relative intensities of the hyperfine transitions are also derived. Application of the theory is stressed in an expository manner.
Linearization of Schwarzschild's Line Element: Application to the Clock Paradox
Authors: Broucke R.
Published: August 2005

This article studies the relativistic theory of the motion of a particle in the presence of a uniform acceleration field. The problem is introduced as a linearization of the fundamental line element of general relativity. The linearized line element is a solution of Einstein's field equations. The equations of geodesics corresponding to this line element are solved and applied to the clock paradox problem.
Physics for Musicians
Authors: Rossing Thomas D.
Published: August 2005

A musical acoustics course, which stresses laboratory work in electronics and acoustical measurements, is described. Through this course, the instructor and several students have become interested in electronic music and have constructed a computer-controlled electronic music synthesizer. Courses of this type, which present physics to musicians and artists, are particularly significant because of the similarities between science and the arts.
Equivalence of the Zeroth and Second Laws of Thermodynamics
Authors: Luckhardt Stanley C. , Kessler John O.
Published: August 2005

The interdependence of the zeroth and second laws of thermodynamics is demonstrated by the interrelation of conceptual perpetual motion machines that violate these laws.
Mechanical Analogs of Time Dependent Josephson Phenomena
Authors: Sullivan D. B. , Zimmerman J. E.
Published: August 2005

The pendulum analog of a small-area Josephson junction between two superconductors is coupled to the analogs of other circuit elements to demonstrate a variety of time dependent phenomena observed with actual devices. The analogy between electrical circuit and mechanical device is established through a Lagrangian formalism. The analog provides a simple and quick means of developing physical insight into this highly nonlinear system. To demonstrate the value of the analog we consider, as one example, the problem of a junction coupled to a resonant cavity and present a result that was missed by a previous solution.
Parametric Phenomena in Physics
Authors: Adler Laszlo , Breazeale M. A.
Published: August 2005

Parametric excitation of a resonant system is a self-excitation caused by a periodic variation of some parameter of the system. A brief history of parametric phenomena is given from Faraday and Lord Rayleigh through modern day physics. The general characteristics of “parametric generators” are viewed through a specific example from acoustics, which is treated in detail.
Steady-State Nuclear Polarizations via Electronic Transitions
Authors: Webb Robert H.
Published: August 2005

Nuclear polarization schemes are surveyed. Special attention is given to those involving saturation of either the direct electronic transitions (Overhauser and “Underhauser” effects) or the weakly forbidden electron-nucleon “cross” transitions (Jeffries and Solid effects). Rate equations are used to find the power dependence of these effects. The physical systems allowing each of these effects are considered in terms of the various types of electron-nuclear coupling. Experimental work and bibliography to date are also surveyed.
Apparatus Drawings Project. Report Number 18. Nuclear Magnetic Resonance Absorption Apparatus
Authors: Marcley Robert G.
Published: August 2005

A nuclear magnetic resonance apparatus of the absorption type, utilizing a one-tube oscillating detector is described. The apparatus can be used to determine the gyromagnetic ratio γ of nuclei, from which their magnetic moment μ can be computed. If operated in conjunction with an Omegatron in the same magnetic field, it permits the determination of μ of the proton directly from two frequency measurements only. Measurements on protons are made with samples of water and common oils, data on fluorine is obtained from the plastic, Teflon. The apparatus is also useful for accurate measurements of magnetic fields. The determination of γ and H can be made with a precision of about ±0.02%. The accessory equipment required consists of a magnet producing a field of several kilogauss, homogeneous to at least 1 part in 103; a frequency meter; a communications receiver; and a cathode-ray oscilloscope.
Adiabatic Invariance in Simple Harmonic Motion
Authors: Parker Leonard
Published: August 2005

We show, in an elementary but apparently new way, that the ratio of the energy to the frequency of a simple harmonic oscillator is an adiabatic invariant. The adiabatic invariance is a consequence of the conservation of angular momentum in the two-dimensional system, of which the one-dimensional harmonic oscillator is the projection. We also briefly discuss the connection between the quantization of angular momentum and the quantization of the oscillator's energy.
Electrons and Positrons—Can Freshmen Get a Charge out of Physics?
Authors: Stevens J. R. , Winegard W. C.
Published: August 2005

A one semester introductory physics course for physical science students emphasizes experimental involvement. PSSC physics and introductory calculus are prerequisite. The first two of three topics concentrate on the properties of the electron, positron, and photon. In the third topic the concepts developed in the previous topics are used to explain the structure of metals, emphasizing the role of defects. In an effort to give students an appreciation for the experimental apparatus of contemporary physical science and to illustrate the ease and speed with which some experimental results can be obtained, relatively sophisticated equipment was used. A detailed discussion of this course and its objectives is given as well as the results of student evaluation. This course has been offered and evaluated twice with encouraging results.
An Aid for Clarifying Space-Time Concepts in Special Relativity
Authors: Evett Arthur A.
Published: August 2005

It is shown how a diagram of two different inertial reference frames, representing the situation at a given instant from the viewpoint of one of the frames, can be used to develop insight into the various space-time effects of special relativity. An analysis is given of a number of thought experiments in which each frame makes its own measurements of various properties and then watches the other frame make similar measurements, Each frame can then interpret the data of the other frame. Measurements of relative speed, speed of light, Lorentz contraction, and time dilation are discussed in this way. Also, the same approach is used to consider causal difficulties arising from the possible existence of faster-than-light particles (tachyons).
Photoelectric Effect and Planck's Constant in th Introductory Laboratory
Authors: Hall Harry H. , Tuttle Richard P.
Published: August 2005

This paper describes another approach to the photoelectric measurement of h/e which is practicable for the introductory laboratory. The method owes its success to a new way of minimizing photoemission by the anode. A common vacuum photocell (1P39) and slit replace the eyepiece and cross hairs of a student grating spectrometer, illuminated by an ac mercury arc. If the cell is favorably oriented to the incident light, photoemission by the anode at high cathode retarding potential (6 V) can be reduced to less than 0.4% of the maximum photocurrent with zero retarding potential at the 3650-Å line. The 120-Hz component is amplified and rectified for presentation on a 100 μA dc meter. The maximum gain is sufficient to indicate full scale for a photocurrent of 10−11 A. Stopping potentials for six lines between 3650 and 5770 Å are determined by plotting the square root of the photocurrent against retarding potential and by extending the straight portions of these plots to the axis. The slope of a straight line drawn through the stopping potentials, plotted against photon frequency, comes close to the accepted value of h/e. Perhaps the most instructive aspect of this experiment is the experience with electron and photon energies. The student observes directly that electrons ejected by uv photons are much harder to stop than those ejected by photons of yellow light.
Mechanical Models for Reactions Involving Isobaric Analog and Doorway States
Authors: Mello P. A. , Moshinsky M.
Published: August 2005

In this paper, we develop a classical mechanical model for nuclear reactions involving isobaric analog and doorway states. The R matrix for the model is identical to the one of the nuclear reaction problem, and the corresponding S matrix gives rise to such characteristic effects as the Robson enhancement factor for the isobaric resonances.
The Penetration of Light Waves beyond a Totally Reflecting Surface
Authors: McDonald W. J. , Udey S. N. , Hickson P.
Published: August 2005

A simple technique is described which demonstrates the penetration of laser light beyond a totally reflecting interface. The method is suitable for a very convincing classroom demonstration and can also be used to obtain quantitative results.
On Renormalized Einstein Phonons and Green Function
Authors: Shukla Ramesh C. , Muller Eric R.
Published: August 2005

The problem of interacting Einstein phonons is treated by deriving the Green function through a functional derivative approach employing the Hamiltonian of Born-von Kaacute;rmán. In this case the Dyson equation yields an exact solution for the Green function whose poles are the frequency versus wave vector dispersion relation. The Green function is used to calculate the internal energy and the Helmholtz free energy of the crystal. The latter is derived by integrating the average interaction energy over the coupling parameter.
A Classical Calculation of Raman Line Shapes
Authors: Laulicht I. , Halpern V.
Published: August 2005

A simple classical method is used to calculate the shape of the emission line and Raman spectrum line of a molecule which behaves like a damped harmonic oscillator. The shapes found, which are similar for the two cases, differ appreciably from the Lorentzian shape and from the shapes found by other authors if the line width is of the same order of magnitude as the natural frequency. Such a situation arises in ferroelectric crystals at temperatures close to that of a second-order phase transition.
Conformal Flatness of the Schwarzschild Interior Solution
Authors: Buchdahl H. A.
Published: August 2005

It is shown that the only static distribution of fluid with nonnegative density and pressure which generates a conformally flat metric through Einstein's equations without cosmical term is that described by the Schwarzschild interior solution. The metric is exhibited in a form in which its conformal flatness is manifest. A transformation of coordinates which occurs in this work is used to obtain the optical point characteristic by a shortcut.
An Undergraduate Optics Experiment on Coherence Length and Bandwidth
Authors: Millet Peter J.
Published: August 2005

An advanced undergraduate optics experiment is described in which the Michelson interferometer is used to study the relationship between the longitudinal coherence length and bandwidth of light from a tungsten filament. Sample student results are presented.
Measurement and Its Reliability: An Introductory Laboratory Experiment
Authors: Poultney Sherman K.
Published: August 2005

An introductory laboratory experiment about measurement and its reliability has been developed for general science students. The experiment keeps their interest by focusing on the measurement outside the classroom of a quantity of daily interest (speeds of automobiles). It allows simple estimates of direct measurement errors, allows the experiment to be designed accordingly, and stresses the reliability (court room defense) of the measurement of the quantity of interest. At the same time, the kinematical concepts of average velocity, instantaneous velocity, and acceleration can be introduced as can the utility of significant figures and graphical display.
Relation between the Binding Energy and Scattering Phase Shift
Authors: Chong K. F. , Nogami Y.
Published: August 2005

It is “well known” in the potential scattering in quantum mechanics that it is, in principle, impossible to obtain information about the binding energy from the scattering phase shift, and vice versa. This is illustrated in a simple way for the case of a nonlocal separable potential. The implications of the “relation” between the deuteron binding energy and the low-energy proton-neutron scattering parameters in the S3 state are discussed.
On Complementary Color Transitions due to Dispersion
Authors: Holtsmark Torger , Valberg Arne
Published: August 2005

The often mentioned indifference of geometrical optics towards particular interpretations of the physical nature of light is discussed from the standpoint that geometrical optics operates in a line continuum. It is shown that, in dispersion experiments, the concept of specific refrangibility applies to pairs of rays in so far as mutually complementary boundary conditions at the aperture are considered. Such pairs of rays are projecting mutually complementary colored images. Finally, some lecture room experiments are proposed, which demonstrate complementary color transitions due to complementary boundary conditions at the aperture.
Fermi's Golden Rule—An Exercise in Quantum Field Theory
Authors: Stedman G. E.
Published: August 2005

The golden rule of time dependent perturbation theory is derived using the formalism of quantum field theory in statistical physics. The proof is more satisfying than that of some conventional presentations and is a simple illustration of the use of the quantum field theoretical formalism (e.g., Green's functions, linked cluster expansions, and Dyson's equation) in the context of solid state theory.
A Note on the Partition Function for Systems of Independent Particles
Authors: Ford D. I.
Published: August 2005

The N-particle Bose-Einstein and Fermi-Dirac canonical partition functions are expressed explicitly in terms of the single-particle partition function. The nature of the approximations made in using corrected Maxwell-Boltzmann statistics is thereby made more obvious. A recurrence relation is developed to facilitate calculations using the exact partition function.
A Demonstration of Lenz' Law?
Authors: Churchill E. J. , Noble J. D.
Published: August 2005

The generally accepted explanation for the jumping ring demonstration is reviewed and shown to be inadequate to describe the observed phenomena. A more complete explanation is brought to the readers' attention in this paper.
The Relativistic One-Dimensional Square Potential
Authors: Adler Carl G.
Published: August 2005

The one-dimensional Dirac equation is applied to the cases of a particle bound in a square well and of a beam of particles impinging upon a square potential. The solutions are compared to the Schrödinger solutions, and the effect of the negative mass states is discussed.
Optics of Thin Metal Films
Authors: Nestell J. E. , Christy R. W.
Published: August 2005

The theory of reflectance and transmittance of light at oblique incidence on a thin metal film is developed in terms of the optical constants n and k. The appropriate substitutions of the complex quantity (n+ik) for the index of refraction in the standard formulas for a dielectric film are justified by physical considerations of energy conservation at the boundary and angle of propagation in the metal. The final formulas for this general case are very complicated, but the availability of computer techniques makes them of practical value for experimental determinations of the optical constants of a metal.
Circuit Analogy for Skin Effect in Conductors
Authors: Kahl G. D. , Weber F. N.
Published: August 2005

The skin effect in a conductor follows formally from a solution of Maxwell's equations. Visualizing the phenomenon from simple physical arguments is difficult and often misleading. This paper presents a parallel circuit analogy for skin effect which exhibits its essential characteristics as well as the inverse skin effect.
Generalized Finite Matrix Hamiltonians
Authors: Trubatch S. L.
Published: August 2005

A Fermion representation is developed for truncated Bose operators. The eigenvalue analysis of finite matrix Hamiltonians becomes transparent by using this representation. Renormalization is discussed independent of of infinities for simple separable cases.
The Energy and Momentum of a Classical Electron in Special Relativity
Authors: Benumof Reuben
Published: August 2005

An equation for the energy of a “classical” electron is derived from Maxwell's equations. The reason for carefully specifying the time at which certain integrations are performed is established. The momentum of the electron is treated in a similar manner. The results are in complete agreement with the special theory of relativity.
The Consortium for the Advancement of Physics Education
Authors: Spangler John D. , Hathaway C. E.
Published: August 2005

In January 1969 Kansas State University joined with six non-Ph.D. granting institutions to form the Consortium for the Advancement of Physics Education (CAPE). CAPE is an experiment to determine what services can be provided for the physics departments of colleges by a university and what benefits can be derived by the university through increased interaction with colleges. Diverse programs, supported mainly by a grant from the National Science Foundation, have been initiated. These programs attempt to capitalize on the strengths and combat the weaknesses of each type of institution. In this article the programs will be described, with special attention given to the CAPE Undergraduate Symposium on Low-Energy Accelerator Physics.
On the Derivation of the Pryce-Foldy-Wouthuysen Transformation
Authors: Cohen H. A.
Published: August 2005

A simple and instructive derivation of the Pryce-Foldy-Wouthuysen transformation is given in terms of rotations in two dimensions.
A Single-Photon Double-Slit Interference Experiment
Authors: Parker Sherwood
Published: August 2005

We describe a double-slit interference experiment suitable for a beginning physics laboratory in which single photons are observed to interfere with themselves, directly demonstrating the wave-particle duality. When the photons are tagged to indicate which slit they passed through, the double-slit interference vanishes. Both the slits and the diffraction pattern are visible to the unaided eye.
A Least-Squares Analysis of the Uncertainty Principle
Authors: Forkosch John
Published: August 2005

This paper finds the statistical best-fit line corresponding to an error term that is taken as the uncertainty product between two conjugate parameters. The average error per observation attributable to this line is then assumed to be greater than a certain minimum value. This restriction results in the finding that successive measurements cannot be obtained arbitrarily close together.
An Elementary Way to Handle a Class of Cosmological Models
Authors: Cavallo Giacomo
Published: August 2005

In calculations of effects of astrophysical interest which require the cosmology to be taken into account, the use of different cosmological models yields different results. An elementary method is given which allows one to estimate the final results starting from the direct computations for a particular model (the Einstein-deSitter universe).
On the Dynamical Approach to the “Clock Paradox”
Authors: Quale Andreas
Published: August 2005

The problem of establishing a dynamical connection between the proper time rate of a standard clock and its physical environment is considered, and the relevance of this for the famous “clock paradox” controversy is discussed. In particular, the possibility of “explaining” this phenomenon as due to a physical interaction between the gravitational field and the clock, governing the rate of the latter, is investigated. We find that one may always introduce formally an “effect” by the field on the clock rate, and thus “resolve the paradox,” as has been done in the literature; however, this “effect” is physically trivial, arising from a conventional choice of coordinates, and can always be “normalized away,” irrespective of the field environment of the clock. It is argued that a nontrivial “dynamical resolution” of the clock paradox must yield a way of predicting the effect of the field on the proper time rate of a clock from local field observations, without observing this rate directly on the clock. It is shown that this requires a number of restrictions to be imposed on the gravitational field environment of the clock and that the field equations of standard relativity theory are not sufficiently restrictive in this respect. Hence, the clock paradox cannot, in principle, be explained as a genuine dynamical phenomenon within this theory.
AAPT Distinguished Service Citations February 1971
Authors: Geballe Ronald
Published: August 2005

Remarks made by the Chairman of the Committee on Awards in presenting the AAPT Distinguished Service Citations for 1970.
Tachyon Paradoxes
Authors: Schulman L. S.
Published: August 2005

It is sometimes inferred from tachyon paradoxes that there is no consistent motion of a system permitting faster than light signals. Using an argument of Wheeler and Feynman, we show how this dilemma can be avoided although in the process there is some modification of the ideas of cause and effect. The resulting point of view is one that has been adopted by science fiction writers concerned with time travel.
Normal-Mode Frequencies of Finite One-Dimensional Lattices with Single Mass Defect: Exact Solutions
Authors: Weinstock Robert
Published: August 2005

The normal-mode longitudinal-vibration frequencies are determined for a finite one-dimensional lattice of mass particles joined by identical massless ideal springs, when at most one of the particle masses differs from all the rest. Results are derived for all boundary conditions of common physical interest by a method that is both elementary and straightforward. The results are expressed through solutions of trigonometric equations readily solvable with arbitrary precision by numerical methods. Considerable information about the solutions is presented by means of simple graphical representations.
Conservation Laws for Gauge-Variant Lagrangians in Classical Mechanics
Authors: Lévy-Leblond Jean-Marc
Published: August 2005

When a physical system has some symmetry properties, it is described by equations of motion invariant under the corresponding transformation group. Its Lagrangian however need not be invariant and may be “gauge-variant,” that is, vary by the addition of a total time derivative. A slightly generalized form of Noether's theorem nevertheless exists in such cases, still leading to conservation laws. The importance of considering such noninvariant Lagrangians and the associated conservation laws is illustrated by several examples: energy conservation, Galilean invariance, dynamical symmetries (harmonic oscillator and Kepler's problem), motion in a uniform electric field.
The Scales of Length and Time in Classical and Modern Physics
Authors: Wolsky Alan M.
Published: August 2005

We consider whether there are uniform changes in the scales of length and time which transform solutions of the equations of motion into other solutions of the equations of motion in classical particle mechanics, nonrelativistic quantum mechanics and relativistic quantum field theory.
Elastic Crystal Models
Authors: Drechsler M.
Published: August 2005

Elastic three-dimensional models of metal crystals are built in which the forces between atoms are represented by coil springs which are under compression or tension even in equilibrium. Each atom of such model automatically takes a position which minimizes the sum of the potential energies of all model springs. Stable bcc models are obtained, if the relative spring forces are adapted to the forces between metal atoms. The self-adjusting lattice constant of some models is measured and calculated. The anisotropy of Young's modulus is measured on models adapted to W, Mo, and Ta. It agrees with the elastic anisotropy on the real crystals. Models are also used to study the position of atoms near the core of a dislocation, around a vacancy, and around an adsorbed atom.
An Extension of the Ramsauer-Townsend Experiment in a Xenon Thyratron
Authors: Woolsey G. A.
Published: August 2005

An experiment on the Ramsauer-Townsend effect in xenon using a 2D21 thyratron, which was originally devised by Kukolich, has been extended to allow for effects due to contact potential and electron emission energy. As well as improving the accuracy of the experiment, this extension serves as a useful method of introducing the concepts of contact potential and electron energy distribution.
Solution of the Mathieu Equation in the WKB Approximation
Authors: Richardson M. J.
Published: August 2005

The Schrödinger equation for a particle in a one-dimensional sinusoidal potential is the Mathieu equation. The usual solution of this equation is in terms of a stability analysis and is given by power series expansions. In this paper, the Mathieu equation is discussed as a Schrödinger equation, and stability is interpreted in terms of allowed and forbidden energy bands. It is shown how simple physical arguments and use of the WKB approximation lead easily to the stability diagram given but not derived in most texts.
Limits of the Adiabatic Approximation
Authors: Spavieri Gianfranco
Published: August 2005

The exact solution for the motion of a particle with charge e and mass m, moving in a spatially uniform magnetic field with the time variation B(t) = B0e−t/τ, is given in the nonrelativistic case. The trajectory of the particle has been plotted for various values of τ and limits are given for the validity of the “adiabatic approximation” and the “sudden approximation”.
The Polarization of Phonons in Cubic Crystals
Authors: Borcherds P. H.
Published: August 2005

The secular equations for elastic waves in cubic crystals are solved for all algebraically possible cases. It is shown that longitudinal waves can be propagated along (ξ, ξ, ξ), (ξ, ξ, 0), and (ξ, 0, 0) only, and that one transverse mode exists for waves with vector (h, k, k) or (h, k, 0).
Potentials as the Result of Unobserved Degrees of Freedom
Authors: Iddings C. K. , Teague M.
Published: August 2005

Following a proposal of Hertz, we show that the one-dimensional motion of a point mass in a potential is dynamically equivalent to free particle motion of the particle in a curved space of two dimensions, where one of the coordinates is cyclic and is not observed. We consider both the classical and quantum mechanical cases.
Hamilton-Jacobi Perturbation Theory
Authors: Ferrell Thomas L.
Published: August 2005

The Hamilton-Jacobi theory is extended to include classical perturbation theory. Examples are given to illustrate the power and elegance of the procedure.
James Clerk Maxwell and the Kinetic Theory of Gases: A Review Based on Recent Historical Studies
Authors: Brush Stephen G.
Published: August 2005

Maxwell's four major papers and some shorter publications relating to kinetic theory and statistical mechanics are discussed in the light of subsequent research in those subjects. Further information about the origin and development of Maxwell's ideas, based on study of unpublished materials and closer examination of less well-known articles, is reviewed, with reference to topics such as the velocity distribution law, the theory of heat conduction, the mechanism of the radiometer effect, the ergodic hypothesis, and Maxwell's views on the history of science.
Apparatus for Detection of Open Orbits on the Fermi Surface Using the Induced Torque Method
Authors: Kolomeychuk R. J. , Dixon A. E.
Published: August 2005

When a single crystal metal sample, is suspended in a slowly rotating magnetic field at liquid helium temperatures, a torque is produced as a result of induced currents in the sample. The torque has a sharp maximum whenever the magnetic-field direction is perpendicular to an open orbit on the Fermi surface. A simple and robust torque magnetometer, constructed as part of a senior laboratory project, is described. Open orbits on the Fermi surface of a cadmium sample were observed in magnetic fields as low as 2000 G; magnetic breakdown of the open orbit was observed at higher fields.
Measurement Objectives in Plasma Physics
Authors: Menkes J.
Published: August 2005

The characterization of plasmas in terms of the deviations from thermodynamic equilibrium is proposed. For this characterization to be meaningful, the measurements have to be independent of the constraints on the plasma. The distinction between intensive and extensive variables and the relationship between calibration of a measuring device and the interpretation of the data in an actual experiment are brought out. Finally, the commonly used measurement techniques are examined as to their suitability to effect the characterization proposed and the limits of applicability are pointed out.
Resource Letter IQM-1 on the Interpretation of Quantum Mechanics
Authors: Dewitt Bryce S. , Graham R. Neill
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters. This is one of a series of Resource Letters on various topics, intended to guide college physicists to literature and other teaching aids that may help them improve course content in specified fields of physics. No Resource Letter is meant to be exhaustive and complete. In time, there may be more than one letter on some of the main subjects of interest. Comments and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed and should be addressed to Professor Joel E. Gordon, Chairman, AAPT Committee on Resource Letters, Department of Physics, Amherst College, Amherst, Mass. 01002.

Notation: The letterEafter an item indicates elementary level, useful principally for high school and introductory college use; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material, principally suited for senior, graduate level. An asterisk (*) indicates items particularly recommended for introductory study.
Modern Biology for Physics Graduate Students
Authors: Finegold Leonard
Published: August 2005

The problem of introducing modern biology to physics graduate students is discussed briefly. An outline is given of a physics-in-biology course at the University of Colorado, together with comments on the literature used in the course.
Estimating Sums with Integrals
Authors: Boas R. P. , Stutz C.
Published: August 2005

Three methods of converting sums to integrals are presented in the hope that it will be possible for students and instructor to make such conversions with a better knowledge of the errors introduced.