1998/06/15 by A. Calogeracos, A Calogeracos, Norman Dombey +1 · 4 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum Electrodynamics and Casimir Effect #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1142/s0217751x99000312
published as Int.J.Mod.Phys. A14 (1999) 631-644 · 17 pages
arxiv created 1998/06/15 · openalex publication_date 1999/02/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/02
The Klein paradox is reassessed by considering the properties of a finite square well or barrier in the Dirac equation. It is shown that spontaneous positron emission occurs for a well if the potential is strong enough. The vacuum charge and lifetime of the well are estimated. If the well is wide enough, a seemingly constant current is emitted. These phenomena are transient whereas the tunnelling first calculated by Klein is time-independent. Klein tunnelling is a property of relativistic wave equations, not necessarily connected with particle emission. The Coulomb potential is investigated in this context: it is shown that a heavy nucleus of sufficiently large Z will bind positrons. Correspondingly, it is expected that as Z increases the Coulomb barrier will become increasingly transparent to positrons. This is an example of Klein tunnelling.