frozen light ?

Question

I ve heard of this Bose Einstein Condensater. Not sure what it does, can some plz explain?

Also i ve heard that it can freeze light to a stand still ! is this really possible..... how will the nature of photons change if so??

Answer 1

Something is considered to be a Bose-Einstein Consensate when all of the atomic elements align in the same direction, giving all sorts of unusual properties to them. But it can only be bosonic particles, not fermions. An example of a BE Condensate is the Helium-4 Supefluid. Superfluids have the unusual property of having no viscosity, and will actually flow up the walls of a container! Superconductivity is another example of BE Condesation. Superconductivity occurs at extremely low temperatures in certain materials, the effect of which is absolutely zero electrical resistance in the material. Superconductors are used in our large particle accelerators, because it reduces the amount of power necessary to accelerate the particles to almost the speed of light. If there was normal electrical resistance, we would never be able to acclerate the particles to the speed required!

On freezing light: We cant stop it totally, but the speed of light depends on the medium it travels through. For instance, the interior of the Sun is so dense, and it slows light so much, that it takes light 200,000 years to reach the surface, but when it hits the vacuum of space, it accelerates back to 186,282.397 miles per second, and reaches the earth in around 8 1/2 minutes. When scientists say "the speed of light", they are almost always referring to the speed of light in a vacuum, with nothing to interfere with it. There was an experiment recently that did 'halt' a beam of light, but on the atomic scale it was more like a reflection/refraction effect that didnt allow the light to continue further. anyway, hope this helps and the link below contains the article on 'stopping' light, you cant read the whole thing but you can order it if you really want, its the real Astract by the guys that conducted the experiment.

Answer 2

"A Bose–Einstein condensate is a state of matter formed by bosons cooled to temperatures very near to absolute zero (0 kelvins or -273.15 degrees Celsius). Under such supercooled conditions, a large fraction of the atoms collapse into the lowest quantum state, at which point quantum effects become apparent on a macroscopic scale."
from:
http://en.wikipedia.org/wiki/Bose-Einstein_condensate

photons do not freeze. they don't even slow down. one of the principles of modern physics is that photons are always moving at the speed of light and that the observed value for the speed of light is the same value for all observers in all inertial frames of reference.