摘要:

This paper is a discussion of that perennial question, ‘‘Why does an excited atom radiate?’’ A satisfactory physical picture emerges when proper account is taken of the interplay between radiation reaction and the (quantum‐mechanical) zero‐point fluctuations of the radiation field. The fluctuation‐dissipation connection between these two effects is therefore emphasized.

ISSN:0002-9505    

DOI:10.1119/1.13886

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

It is shown that the eigenvalues of the simple quantum‐mechanical models usually studied in the first courses on Quantum Mechanics can be obtained through a very simple algebraic technique. TheN‐dimensional hydrogen atom, theN‐dimensional isotropic harmonic oscillator, and the Morse oscillator are discussed as illustrative examples.

ISSN:0002-9505    

DOI:10.1119/1.13665

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Since Einstein’s first publication on relativity many papers have been published on the logical derivation of the Lorentz transformations, but apparently without any conclusiveness on the subject having been reached. In this paper, by basing the analysis of this problem on purely kinematic postulates that can be shown to be necessary, an attempt is made to achieve a degree of definitiveness in the results that would enhance their usefulness in ongoing studies on the conceptual foundations of relativistic physics.

ISSN:0002-9505    

DOI:10.1119/1.13666

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Elementary ideas on pulse shapes from ionization chambers are reviewed. Ramo’s theorem, and a plausible interpretation of it, are discussed and the results applied to semiconductor detectors. The complication of plasma formation is briefly referred to.

ISSN:0002-9505    

DOI:10.1119/1.13667

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A generalized Helmholtz’s theorem is proved, which states that an antisymmetric second‐rank tensor field in 3+1 dimensional space‐time, which vanishes at spatial infinity, is determined by its divergence and the divergence of its dual. When the divergence of the antisymmetric electromagnetic field strength tensor is equal to the electric charge‐current density and the divergence of the dual of the electromagnetic field strength tensor is equal to the magnetic charge‐current density, the equations of electromagnetism are obtained. As a convenience, in the solution of the equations of electromagnetism two different four‐vector potentials can be used, one of which couples to the electric charge‐current density and the other to the magnetic charge‐current density.

ISSN:0002-9505    

DOI:10.1119/1.13668

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

We propose a simple method for solving some electrostatic problems normally treated by images. The method is based on the multipole expansion of the electrostatic potential due to both real and image charges. The magnitude and the location of the image charges are found by imposing the proper boundary conditions. Some typical problems with spherical and with spheroidal symmetries are worked out explicitly.

ISSN:0002-9505    

DOI:10.1119/1.13669

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Stirling’s approximation ton!  and other estimates, some cruder, some more refined, are developed along surprisingly elementary lines. The aim is to shed some light on why these approximations work so well, for students using them to study entropy and irreversibility in such simple statistical models as might be examined in a general education physics course. At the heart of the argument is an elementary and useful representation ofallthe corrections to Stirling’s approximation, with which even many experts seem to be unacquainted.

ISSN:0002-9505    

DOI:10.1119/1.13670

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.13671

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.13672

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.13673

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP