摘要:

Ehrenfest’s theorem states that as a quantum state evolves in time, the rate of change of the expectation value of momentum is equal to the expectation value of the force. In the familiar ‘‘particle‐in‐a‐box,’’ however, the probability of finding the particle at a wall—the only place where forces act—is zero, so at first glance it appears that the expectation value of the force should vanish for any state, which would violate Ehrenfest‘s theorem. This argument is flawed, however, since the forces at the walls of the box are infinite. We consider the box as a limit of a very deep square well and confirm that Ehrenfest’s theorem emerges safe and sound.

ISSN:0002-9505    

DOI:10.1119/1.18367

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

摘要:

The ponderomotive and radiation forces acting on a free charge or an atom in an electromagnetic wave are derived in a unified way from the classical Lorentz force equation with radiation damping.

ISSN:0002-9505    

DOI:10.1119/1.18368

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

摘要:

An alternative derivation of the disentanglement formulas for exponential operators, also known as the Baker–Campbell–Housdorff formulas is given for several Lie algebras. The method is especially suited to Lie algebras having no nontrivial center. We also look at some results that can be obtained by the use of these formulas in the case of squeezed coherent states.

ISSN:0002-9505    

DOI:10.1119/1.18183

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18396

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18395

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18457

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18449

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18450

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.18469

出版商:American Association of Physics Teachers    

年代:1996

数据来源: AIP