Wheeler's and Feynman's retarded and advanced waves.

[jdg812]

A while ago, Wheeler and Feynman published a cornerstone paper
Interaction with the Absorber as the Mechanism of Radiation
Rev. Mod. Phys. 17, 157 - 181 (1945)

Briefly, there are two EM waves associated with accelerated charged particle, advanced and retarded waves. According common interpretation, the advanced wave has no physical meaning because of causality principle.

Does anybody have an opinion different from above said about advanced wave?

 

[Andrew Mason]

A while ago, Wheeler and Feynman published a cornerstone paper
Interaction with the Absorber as the Mechanism of Radiation
Rev. Mod. Phys. 17, 157 - 181 (1945)

Briefly, there are two EM waves associated with accelerated charged particle, advanced and retarded waves. According common interpretation, the advanced wave has no physical meaning because of causality principle.

Does anybody have an opinion different from above said about advanced wave?

Feynman talks about this in his very entertaining http://nobelprize.org/nobel_prizes/physics/laureates/1965/feynman-lecture.html" .

He kind of jokes about the advanced wave concept:

First, he said, let us suppose that the return action by the charges in the absorber reaches the source by advanced waves as well as by the ordinary retarded waves of reflected light; so that the law of interaction acts backward in time, as well as forward in time. I was enough of a physicist at that time not to say, "Oh, no, how could that be?" For today all physicists know from studying Einstein and Bohr, that sometimes an idea which looks completely paradoxical at first, if analyzed to completion in all detail and in experimental situations, may, in fact, not be paradoxical. So, it did not bother me any more than it bothered Professor Wheeler to use advance waves for the back reaction - a solution of Maxwell's equations, which previously had not been physically used.

Andrew Mason

 

[jdg812]

Feynman talks about this in his very entertaining http://nobelprize.org/nobel_prizes/physics/laureates/1965/feynman-lecture.html" .

Thanks, indeed entertaining lecture.

 

[CosmosGuy]

Italian physicist http://en.wikipedia.org/wiki/Luigi_Fantappi%C3%A8" into this phenomenon in 1941:

“Suddenly I saw the possibility of interpreting a wide range of solutions (the anticipated potentials) of the wave equation which can be considered the fundamental law of the Universe. These solutions had been always rejected as “impossible”, but suddenly they appeared “possible”, and they explained a new category of phenomena which I later named “syntropic”, totally different from the entropic ones, of the mechanical, physical and chemical laws, which obey only the principle of classical causation and the law of entropy. Syntropic phenomena, which are instead represented by those strange solutions of the “anticipated potentials”, should obey two opposite principles of finality (moved by a final cause placed in the future, and not by a cause which is placed in the past): differentiation and non-causable in a laboratory. This last characteristic explained why this type of phenomena had never been reproduced in a laboratory, and its finalistic properties justified the refusal among scientists, who accepted without any doubt the assumption that finalism is a “metaphysical” principle, outside Science and Nature. This assumption obstructed the way to a calm investigation of the real existence of this second type of phenomena; an investigation which I accepted to carry out, even though I felt as if I were falling in a abyss, with incredible consequences and conclusions. It suddenly seemed as if the sky were falling apart, or at least the certainties on which mechanical science had based its assumptions. It appeared to me clear that these “syntropic”, finalistic phenomena which lead to differentiation and could not be reproduced in a laboratory, were real, and existed in nature, as I could recognize them in the living systems. The properties of this new law, opened consequences which were just incredible and which could deeply change the biological, medical, psychological, and social sciences.”

It seems to me that with the recent fabrication of http://en.wikipedia.org/wiki/Metamaterials" , that its time to rethink the role that left-handed radiation might play in nature.

 

[cesiumfrog]

Can't advanced waves be identified with the process of absorption? (The time-symmetric companion to radiation processes.)