| Автор | N C Tsamis |
| Автор | R P Woodard |
| Дата выпуска | 2001-01-07 |
| dc.description | Schwinger used an analytic continuation of the effective action to correctly compute the particle production rate per unit volume for quantum electrodynamics in a uniform electric field. However, if one simply evaluates the one-loop expectation value of the current operator using his propagator, the result is zero! We analyse this curious fact from the context of a canonical formalism of operators and states. The explanation turns out to be that Schwinger's propagator is not actually the expectation value of the time-ordered product of field operators in the presence of a time-independent state, although it is of course a Green function. We compute the true propagator in the presence of a state which is empty at x<sub>+</sub> = 0 where x<sub>+</sub>≡(x<sup>0</sup> + x<sup>3</sup>)/(2)<sup>1/2</sup> is the lightcone evolution parameter. Our result can be generalized to electric fields which depend arbitrarily on x<sub>+</sub>. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Schwinger's propagator is only a Green function |
| Тип | paper |
| DOI | 10.1088/0264-9381/18/1/306 |
| Electronic ISSN | 1361-6382 |
| Print ISSN | 0264-9381 |
| Журнал | Classical and Quantum Gravity |
| Том | 18 |
| Первая страница | 83 |
| Последняя страница | 94 |
| Выпуск | 1 |
