MadSci Network: Physics
Query:

Re: What current research is being done to reach (Kelvin's) absolute zero

Date: Wed Jan 27 14:16:44 1999
Posted By: Larry Lurio, Staff, Center for Materials Science and Engineering, IMM-CAT
Area of science: Physics
ID: 916680332.Ph
Message:

Dear Virginia,

In the last ten years or so there has been a real breakthrough in the
quest to reach very low temperatures.  This has been due to techniques
which use lasers to cool gases of atoms.  A laser beam consists of
photons which can collide with atoms in a gas. If the lasers are tuned
just right, the collisions will tend to slow down the gas atoms down more
than speed them up.  There is a whole bag of tricks that can be employed
to lower the temperature this way, and presently it is possible to reach
within one millionth of a degree above absolute zero.  It is, however,
theoretically impossible to get all the way to absolute zero.

I can't give you a detailed explanation of all the techniques, but
if you are interested in looking into this further you should look
up the 1997 Nobel prize in physics which was given in recognition of
laser based cooling.  You can check out the Nobel prize web page at
www.nobel.se  
or you can find printed copies of the Nobel prize speeches in your 
local library.

Larry





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