ISSN:0002-9505    

DOI:10.1119/1.17951

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17953

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18093

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17959

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17960

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

This Resource Letter is a guide to the literature on time and frequency measurement. Journal articles and books are cited for the following topics: frequency standards; methods of characterizing performance of clocks and oscillators; time scales, clock ensembles, and algorithms; international time scales; frequency and time distribution; and applications. [The letter E after an item indicates elementary level or material of general interest. The letter I, for intermediate level, indicates material of somewhat more specialized nature, and the letter A indicates rather specialized or advanced material. The designations E/I and I/A are used to indicate that the article contains material at both levels, so that at least part of the article is written at the lower of the two levels.]

ISSN:0002-9505    

DOI:10.1119/1.17961

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

We present detailed instructions for the construction and operation of an inexpensive apparatus for laser cooling and trapping of rubidium atoms. This apparatus allows one to use the light from low power diode lasers to produce a magneto‐optical trap in a low pressure vapor cell. We present a design which has reduced the cost to less than $3000 and does not require any machining or glassblowing skills in the construction. It has the additional virtues that the alignment of the trapping laser beams is very easy, and the rubidium pressure is conveniently and rapidly controlled. These features make the trap simple and reliable to operate, and the trapped atoms can be easily seen and studied. With a few milliwatts of laser power we are able to trap 4×107atoms for 3.5 s in this apparatus. A step‐by‐step procedure is given for construction of the cell, setup of the optical system, and operation of the trap. A list of parts with prices and vendors is given in the Appendix.

ISSN:0002-9505    

DOI:10.1119/1.18072

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

The well‐known Zeeman and Stark effects can lead to unusual atomic state dynamics when both magnetic and electric fields are present. In this paper we analyze quantum mechanical and classical models of the time evolution of the angular momentum of an atom in the presence of weak, orthogonal electric and magnetic fields. The anisotropic electric polarizability of the atom plays a crucial role in the dynamics. The classical model leads to nonlinear evolution equations, and we investigate how quantum mechanics ‘‘avoids’’ the nonlinearity. Finally, we note that the classical equations of motion are identical to those used to describe the time evolution of Stokes vectors for polarized light propagating in an optically nonlinear medium. The treatment is appropriate for an undergraduate course in quantum mechanics.

ISSN:0002-9505    

DOI:10.1119/1.17962

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

In his last memoir on mathematical physics, Henri Poincaré presented one of the most profound and compelling proofs of the hypothesis of quanta. This highly original proof, which is actually three separate proofs, is based on first principles and is full of physical insight, mathematical rigor, and elegant simplicity. The memoir is refreshingly uncluttered by some of the conventional, and more abstract concepts, such as temperature and entropy, that Planck and others relied on in their work. Poincaré’s analysis is based on an ingenious physical model consisting of long‐period resonators interacting with short‐period resonators. A unique formulation of statistical mechanics, based on the calculus of probabilities, Fourier’s integral, and complex analysis, logically unfolds throughout the memoir. Poincaré invents an ‘‘inverse statistical mechanics’’ that allows him to prove a crucial result that no one had proved before: The hypothesis of quanta is both a sufficient and anecessarycondition to account for Planck’s law of radiation. In a separate, more universal proof, Poincaré proves that the existence of a discontinuity in the motion of a resonator is necessary to explainanyobserved law of radiation. Given the significant impact of Poincaré’s memoir on quantum theory and statistical physics, it is surprising that most physicists are not aware of its valuable mathematical and physical ideas. Poincaré’s tour de force proofs are presented here in a form suitable for use in a standard course in quantum mechanics, statistical mechanics, or mathematical physics.

ISSN:0002-9505    

DOI:10.1119/1.17919

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP

摘要:

We have extended the work of others in developing a model for the motion of a ball on a rotating turntable. The numerical model does not impose the constraint of rolling without slipping, and includes both rolling and sliding friction. Computer output from the model is compared with experimental trajectories obtained from time exposures, and found to be in excellent agreement.

ISSN:0002-9505    

DOI:10.1119/1.17920

出版商:American Association of Physics Teachers    

年代:1995

数据来源: AIP