Causal Wave Propagation for Relativistic Massive Particles: Physical Asymptotics in Action
Saved in:
| Title: | Causal Wave Propagation for Relativistic Massive Particles: Physical Asymptotics in Action |
|---|---|
| Language: | English |
| Authors: | Berry, M. V. |
| Source: | European Journal of Physics. Mar 2012 33(2):279-294. |
| Availability: | Institute of Physics Publishing. The Public Ledger Building Suite 929, 150 South Independence Mall West, Philadelphia, PA 19106. Tel: 215-627-0880; Fax: 215-627-0879; e-mail: info@ioppubusa.com; Web site: http://www.iop.org/EJ/journal/EJP |
| Peer Reviewed: | Y |
| Physical Description: | |
| Page Count: | 16 |
| Publication Date: | 2012 |
| Document Type: | Journal Articles Reports - Descriptive |
| Education Level: | Higher Education |
| Descriptors: | Causal Models, Graduate Students, Science Instruction, Physics, Scientific Concepts, Quantum Mechanics, College Science, Equations (Mathematics) |
| DOI: | 10.1088/0143-0807/33/2/279 |
| ISSN: | 0143-0807 |
| Abstract: | Wavepackets representing relativistic quantum particles injected into a half-space, from a source that is switched on at a definite time, are represented by superpositions of plane waves that must include negative frequencies. Propagation is causal: it is a consequence of analyticity that at time t no part of the wave has travelled farther than "ct", corresponding to the front of the signal. Nevertheless, interference fringes behind the front travel superluminally. For Klein-Gordon and Dirac wavepackets, the spatially integrated density increases because current is injected at the boundary. Even in the simplest causal model, understanding the shape of the wave after long times is an instructive exercise in the asymptotics of integrals, illustrating several techniques at a level suitable for graduate students; different spatial features involve contributions from a pole and from two saddle points, the uniform asymptotics for the pole close to a saddle, and the coalescence of two saddles into the Sommerfeld precursor immediately behind the front. (Contains 6 figures.) |
| Abstractor: | As Provided |
| Number of References: | 18 |
| Entry Date: | 2012 |
| Accession Number: | EJ983107 |
| Database: | ERIC |
Be the first to leave a comment!
