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Buckeye
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How does Vacuum Polarization help us ?
In quantum physics, if we expand about the Fock vacuum, the true vacuum contains short-lived "virtual" particle-antiparticle pairs which are created in pairs out of the Fock vacuum and then annihilate each other. Some of these particle-antiparticle pairs turn out to be charged, eg. virtual electron-positron pairs. Such charged pairs act as an electric dipole.
In the presence of an electric field, e.g. an electromagnetic field around an electron, these particle-antiparticle pairs reposition themselves, thus partially counteracting the field (a partial screening effect, a dielectric effect). The field therefore will be weaker than would be expected when the vacuum would be completely empty.
How does filling "empty" space with virtual particles that generate instantaneous (virtual) EM fields help us to understand, say, the movement of photons from point A to Point B, OR How do those VPs help understand the feasibility of Zero Point Energy? These are the sort of questions that Vacuum Polarization might provide support for. I'm also interested in any other applications of Vacuum Polarization. Thanks!Morbid Steve said:Quoted from http://en.wikipedia.org/wiki/Vacuum_polarization"
Buckeye said:How does filling "empty" space with virtual particles that generate instantaneous (virtual) EM fields help us to understand, say, the movement of photons from point A to Point B
How does Vacuum Polarization come into the picture for the 1st or 3rd cases? Thanks!lonelyphysicist said:We can ask the following question: Do photons ever interact with each other? When we cross two laser beams, do we get any light that gets kicked out sideways or do something funny? Or, in Star Wars lingo, are light savers really possible?
If Maxwell's equations are the exact laws of nature, then no, photons cannot interact with each other because Maxwell's equations are linear and so photons must obey the superposition principle - they'll pass right thru each other.
However, in quantum electrodynamics, photons can interact with each other by exchanging virtual electrons, muons, taus, and quarks. This means it is possible for two photons to "meet", interact, and then fly off in a different direction from their initial path.
Buckeye said:How does Vacuum Polarization come into the picture for the 1st or 3rd cases? Thanks!
Buckeye said:How does Vacuum Polarization help us ?
No no no, please forget that analogy.Buckeye said:Thanks Marlon. That helped a bit, so I guess I'm asking: Does Vacuum Polarization serve as a vehicle (means) for photons to move from point A to Point B outside of any atomic structure or beams of particles?
Buckeye said:Many thanks EL and Marlon. Now for a bit of reading...
Vacuum polarization is a quantum phenomenon in which virtual particles spontaneously appear and disappear in a vacuum. These particles, usually in the form of electron-positron pairs, form an electric field that interacts with the original field, causing a shift in its strength and direction.
Vacuum polarization is invoked to explain certain physical phenomena, such as the Lamb shift in the energy levels of hydrogen atoms and the Casimir effect between two parallel conducting plates. It is also important in quantum field theory, where it is used to renormalize certain equations and remove infinities that arise in calculations.
Vacuum polarization causes the vacuum to have a non-zero energy density, which is known as the vacuum energy. This energy can have effects on the physical properties of the vacuum, such as its refractive index and its ability to propagate electromagnetic waves.
Virtual particles are particles that exist for a very short time due to the uncertainty principle. In vacuum polarization, these particles form an electric field that interacts with the original field, causing a shift in its strength and direction. Without virtual particles, vacuum polarization would not occur.
Yes, vacuum polarization has been observed and confirmed through various experiments and calculations. It is an important concept in quantum field theory and has been used to explain and predict various physical phenomena. However, there is ongoing research and debate about the exact nature and implications of vacuum polarization.