摘要:

The logarithmic part of the Lamb shift in hydrogen is related to the usual infrared divergence and can be obtained immediately from the corresponding radiative correction to the Coulomb scattering amplitude. By a simple generalization of Welton’s arguments we get one of the recoil contributions. To complete the recoil calculation one has to include an elementary iteration of the Thomson amplitude. In this way we derive also the logarithmic part of the Lamb‐shift operator in positronium and many‐electron atoms.

ISSN:0002-9505    

DOI:10.1119/1.17714

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

摘要:

Radiative transitions in atoms are formulated as multipole radiations from a localized charge‐current distribution. The correspondence between the relativistic quantum mechanical and classical electrodynamic treatments is demonstrated explicitly. Definitions for multipole moments, line strengths, and oscillator strengths in relativistic quantum mechanics are also summarized.

ISSN:0002-9505    

DOI:10.1119/1.17715

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

摘要:

Equations for the electric and magnetic fields of a point charge moving with constant velocity are derived from retarded integrals representing solutions of Maxwell’s equations for electric and magnetic fields of arbitrary time‐dependent charge and current distributions. In contrast to conventional derivations, the derivations presented here are based exclusively on general electromagnetic field equations and do not make use of retarded potentials or relativistic equations. The derivations lead to some notable conclusions concerning the electric and magnetic fields of an arbitrary charge distribution moving with constant velocity.

ISSN:0002-9505    

DOI:10.1119/1.17716

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

摘要:

Detailed instructions for producing and separating C60and C70are presented. The experiment involves elements of both physics and chemistry. After initial setup of the equipment, results are obtainable within a few hours. Additional experiments for observing physical properties of the fullerenes are suggested. A complete list of equipment is provided, with vendors and catalog numbers, for those wishing to duplicate the experiment.

ISSN:0002-9505    

DOI:10.1119/1.17717

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

摘要:

What is the fastest way to cool something? If the object is macroscopic it is to lower the surrounding temperature as much as possible and let Newton’s cooling law take effect. If we enter the microscopic world where quantum mechanics rules, this procedure may no longer be the best. This is shown in a simple example where we calculate the optimum cooling rate for an asymmetric two‐state system.

ISSN:0002-9505    

DOI:10.1119/1.17718

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17719

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17720

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17721

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.17723

出版商:American Association of Physics Teachers    

年代:1994

数据来源: AIP