- #1
DaveLush
- 53
- 0
It's widely known that the electromagnetic wave equation admits of time-advanced as well as time-retarded solutions, but the time-advanced solutions are often simply discarded as non-physical. This is reasonable enough in many contexts, but I am personally of an opinion that the time-advanced solutions are as evidently necessary as the time-retarded ones. I'm wondering if this would be considered a fringe view or if this is conventional wisdsom. Also, I'm wondering if there is an obvious flaw in my reason for thinking this way, so I will explain my justification, and everyone can respond derisively or otherwise as they see fit.
First, consider the retarded Lienard-Wiechert fields. These are the explicit fields that result from the movement of point charges. Also, it is well-known that there are time-advanced equivalents for the L-W fields. These are sometimes employed in the literature (by e.g. Wheeler-Feynman absorber theory, Eliezer, Dirac classical electron theory, others) but I gather that these are consider esoteric and hypothetical usages. (Am I wrong?) Seems to me though that they are just as necessary to physical theory as the time-retarded ones, for one simple reason. The reason is, that the time-advanced solutions are describing how the charges move in response to the fields. Without the time-advanced part, there can be no electrodynamics, because the charges cannot move in response to the fields. Is this crazy thinking or conventional wisdom or something in between?
First, consider the retarded Lienard-Wiechert fields. These are the explicit fields that result from the movement of point charges. Also, it is well-known that there are time-advanced equivalents for the L-W fields. These are sometimes employed in the literature (by e.g. Wheeler-Feynman absorber theory, Eliezer, Dirac classical electron theory, others) but I gather that these are consider esoteric and hypothetical usages. (Am I wrong?) Seems to me though that they are just as necessary to physical theory as the time-retarded ones, for one simple reason. The reason is, that the time-advanced solutions are describing how the charges move in response to the fields. Without the time-advanced part, there can be no electrodynamics, because the charges cannot move in response to the fields. Is this crazy thinking or conventional wisdom or something in between?