摘要:

The quantization of the Thomson atom through the Wilson–Sommerfeld rules is presented. It is found that the Thomson model is inconsistent.

ISSN:0002-9505    

DOI:10.1119/1.13824

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The hyperfine structure Hamiltonian for hydrogen is derived by evaluating the magnetic field at the nucleus due to the electron’s spin current density. This approach clearly separates the treatment of states withl=0 (Fermi contact term) from those havingl≠0.

ISSN:0002-9505    

DOI:10.1119/1.13846

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A simple apparatus is described in which the deflection of a pendulum with an electromagnet mounted at its tip is the analog of the magnitude of the order parameter in a phase transition. Its deflection is governed by the current through this electromagnet and currents through fixed electromagnets just below it. By suitable variation of these currents, the pendulum can be made to undergo gradual (second‐order transition analog) or sudden (first‐order transition analog) displacements from the vertical, as well as the intermediate situation corresponding to a tricritical point. Results for critical and tricritical exponents obtained with this apparatus are presented.

ISSN:0002-9505    

DOI:10.1119/1.13847

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The relation representing the fluctuation–dissipation theorem for a free Brownian particle suspended in a fluid is derived from first principles using a simple model for the collisions of fluid molecules on a Brownian particle. This result is crucial in deriving the probability distribution for the velocity of a Brownian particle from the Langevin equation. The assumptions used in the model and its implications are also discussed.

ISSN:0002-9505    

DOI:10.1119/1.13848

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The one‐dimensional scattering problem for dissipative media is formulated in terms analogous to the three‐dimensional problem. A model simulating dissipative media is used to numerically evaluate the various quantities defined in this paper.

ISSN:0002-9505    

DOI:10.1119/1.13849

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

The theoretical results for the diffraction of electrons by a disk and a pair of rectangular slits is derived from the Schrödinger equation using results from time‐dependent perturbation theory in both the strong and weak scattering limits. The double‐slit ‘‘thought’’ experiment is often used in introductions to quantum mechanics as a demonstration that electrons have wave‐like properties. It seems desirable to include a derivation of the result both as an interesting example and also as reassurance that the diffraction of ‘‘matter waves’’ leads to the same results as the diffraction of electromagnetic waves by the same obstacle.

ISSN:0002-9505    

DOI:10.1119/1.13850

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A bidimensional model of an ideal gas has been studied to simulate the evolution of the speed distribution. In the model all the molecules are assumed to be hard disks, the collisions between them are assumed to be elastic, and the distribution of the impact parameters is assumed to be a uniform one. By starting from different initial distributions, it is shown that the system always evolves towards the Maxwell–Boltzmann distribution.

ISSN:0002-9505    

DOI:10.1119/1.13809

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Hestenes’ geometric algebra and Pauli’s two‐component spinors are reviewed and are united into a simple mathematical system. The resulting formalism is used to develop a new method for spin 1/2 projection calculations and is also applied to a spin 1/2 electron magnetic resonance problem.

ISSN:0002-9505    

DOI:10.1119/1.13810

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

Nonrelativistic quantum‐mechanical scattering in two dimensions is studied numerically by integrating the time‐dependent Schrödinger equation. A partial‐wave analysis is used to discuss the numerical results. A potential barrier, a square well and a single slit are considered as the scattering potentials.

ISSN:0002-9505    

DOI:10.1119/1.13811

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP

摘要:

A mechanical model of a classical many‐body system is described. Basic ideas and phenomena concerning both the fluid and solid states are illustrated by a series of simple experiments.

ISSN:0002-9505    

DOI:10.1119/1.13812

出版商:American Association of Physics Teachers    

年代:1984

数据来源: AIP