Timeline for How is a spherical electromagnetic wave emitted from an antenna described in terms of photons?
Current License: CC BY-SA 2.5
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| Aug 6, 2011 at 23:57 | comment | added | Marty Green | "If the frequency and angular momentum of the photon is known, its position - direction in which it propagates - is completely unknown". Surely Lubos wrote this in haste. The relevant uncertainties for this problem are the initial position of the "photon", presumed to be completely known, and its final momentum, presumed to be completely unknown. In fact it's a little more suttle: even for a fixed initial position, we can specify one axis along which the momentum is known to be zero; but that's as much as I can say in 600 characters or less. | |
| Feb 4, 2011 at 15:28 | comment | added | anna v | @BuckyBadger , I hope it is clear to you that the classical wave distributions are a limiting case of the quantum mechanical description. Quantum mechanical solutions are always there, except it is not practical or reasonable to use its formalism when the limiting classical formalism is more than adequate. | |
| Feb 4, 2011 at 7:33 | history | edited | Luboš Motl | CC BY-SA 2.5 |
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| Jan 19, 2011 at 2:42 | comment | added | Carl Brannen | For some reason, my instinct is that a spherical electromagnetic wave cannot be emitted by an antenna. Instead, they can only be emitted by a charge. I guess that's cause I always think of an antenna as an object that has no net charge. | |
| Jan 17, 2011 at 22:43 | comment | added | BuckyBadger | Ok Lubos, so I think if I understand you correctly the classical laws of electromagnetism are actually describing the "collective" behavior of what in practice can be considered an infinite number of photons being "spit out" in all directions "simultaneously" or in a more restricted set of directions depending on the configuration of the antenna. Whereas quantum mechanics is used to describe the case of a single photon. So obviously I was confusing the case of "infinite" number of photons with the case of a single photon. Many thanks for your help! | |
| Jan 17, 2011 at 16:09 | history | answered | Luboš Motl | CC BY-SA 2.5 |