Can light quanta stops its moving?

Can light quanta stops its moving?

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Can light quanta stops its moving?

Postby mainchin » Tue Aug 18, 2009 8:30 am

Quantum mechanics describes the bizarre rules of light and matter
on atomic scales. In that realm, matter can be in two places at once.
Objects can be particles and waves at the same time.
And nothing is certain -- only probable or improbable.

This improbable feat -- stopping light -- was accomplished by two teams.
One was led by Ron Walsworth, a physicist at the Harvard-Smithsonian Center for Astrophysics, and the other by Lene Hau of Harvard University's Department of Physics. Walsworth's group used warm rubidium vapors to pause their laser beam; Hau's group used a super-cold sodium gas to do the same thing.

http://science.nasa.gov/headlines/y2002/27mar_stoplight.htm
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Can light quanta stops its moving?

Postby jedi41 » Tue Aug 18, 2009 8:35 am

First of all a photon is not a particle nor a waves by definition as you indicate its only a "quanta". That means its a mathematical construct to explain the energy of light in terms of the radiation power falling a unit area. A photon is therefore not a true description of what light is per se.
So Unless a better theory explains what light is,there is no direct answer to your question.We cannot assume a mathematical construct to be an entity,since theories of physics insist that its a massless volume of energy. As per The physisits Richard Feynman,He indicated that scientists really do not understand what is "Energy" . So if they dont understand it ,let alone the Power of light.
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Can light quanta stops its moving?

Postby bronson » Tue Aug 18, 2009 9:10 am

yes, various people have got small (v. small) amounts of photons to stop. Refer to physics world magazine (complicated answers) or new scientist or scientific american (easier anwers)
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Can light quanta stops its moving?

Postby evelyn » Tue Aug 18, 2009 9:26 am

The first correction, a particle can't be in two places at the same time, it just has an equal probability of being in those two places, for example look at the double slit experiment for a single electron. Now, could you tell which slit the electron passed through? No, even if we had instruments to look at it, it will disrupt the wave. But there is an equal probability that the electron passes through either slit, not both at the same time.
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Can light quanta stops its moving?

Postby bama » Tue Aug 18, 2009 9:46 am

One of the parameters for a photon is that it must be in motion.
Stopping and containing a photo is a priority of IC builders.
As far as I know no one has accomplished it yet.
A photo must be kept in a constant state of acceleration to exist.
Researcher are working with a reverse opal that may eventually do what they want.
To contain a photon and be able to control it as a gate in a logic circuit.
It is a highly competitive quest so you may not be able to get too much information on the subject
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Can light quanta stops its moving?

Postby bocley » Tue Aug 18, 2009 10:42 am

"...matter can be in two places at once..."

What you may be thinking of in the above statement is known as 'spooky-action-at-a-distance' or 'quantum entanglement.' Two identical particles can be separated by vast distances (..light years..) and if one particle is changed in some way, the twin particle will instantaneously alter itself to match. This does not imply in any way that an individual particle exists in two places at once.
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Can light quanta stops its moving?

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