Discovering the Secrets of Absolute Zero: Scientists' Techniques Revealed

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In summary, scientists have been able to cool small samples of atoms to incredibly low temperatures, just one ten-billionth of a degree above absolute zero, using a technique called laser cooling. This involves using carefully tuned laser frequencies to slow down the movement of atoms and trap them for study. This idea was first proposed by Nobel Prize winner Steven Chu, and has since been demonstrated by other scientists, such as William Phillips. Chu has emphasized the importance of encouraging imaginative thinking in scientific research.
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KLscilevothma
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I was reading Discover (November 2003), on pg 18 Ask Discover, it says "Absolute zero cannot be reahed experimenally, but scientsts have cooled small samlples of atoms to just one ten-billionth of a degree above absolute zero."

How could scietists cool the sample to such a low temperature ?
 
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  • #2
Originally posted by KL Kam
I was reading Discover (November 2003), on pg 18 Ask Discover, it says "Absolute zero cannot be reahed experimenally, but scientsts have cooled small samlples of atoms to just one ten-billionth of a degree above absolute zero."

How could scietists cool the sample to such a low temperature ?

Hey KL :wink:

LASER Cooling
Laser trapping and cooling does just that. Photons, the quanta of light, carry momentum. When an atom absorbs a photon, the photon's momentum gives the atom a kick in the direction the photon was traveling. The atom can only absorb a photon if the photon's energy matches the energy difference between two of the atom's energy levels. Careful tuning of the laser frequency insures that only atoms moving toward the light can absorb photons and be slowed.
http://www.physicscentral.com/action/action-00-4.html

The idea of using lasers to trap and cool molecules for study began over a lunchtable conversation at Bell Labs in Holmdel, N.J. more than 10 years ago. Today, because of his idea, former Bell Labs researcher Steven Chu is one Nobel Prize in Physics richer.

http://www.bell-labs.com/user/feature/archives/chu/


There was no magic involved — just physics — as Nobel Prize laureate William Phillips demonstrated the principles behind his laser cooling and trapping technique to a mystified crowd of students, professors and college alumni, and offered observers a taste of just how cold atoms cooled by the technique are

http://www.sccs.swarthmore.edu/org/phoenix/2001/2001-03-22/news/10875.html


A note on Chu; I saw him a few years ago at Stanford. He spoke for quite some time about the importance of encouraging imaginative thinking.
 
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  • #3
Thanks Ivan.

PS. I was in a hurry and didn't notice those spelling mistakes in the first post.
 

What is absolute zero?

Absolute zero is the theoretical lowest possible temperature that can be achieved, at which point all molecular motion ceases. It is equivalent to 0 Kelvin or -273.15 degrees Celsius.

How do scientists measure absolute zero?

Scientists use a variety of techniques to measure absolute zero, including using temperature scales such as Kelvin and Celsius, measuring changes in gas volume and pressure, and studying the behavior of materials at extremely low temperatures.

Why is absolute zero important?

Absolute zero is important for understanding the behavior of matter at extremely low temperatures, as well as for practical applications such as cryogenics and superconductivity.

What are some of the challenges in reaching absolute zero?

Reaching absolute zero is extremely difficult and requires specialized equipment and techniques. Some of the challenges include preventing heat transfer from the environment, dealing with the effects of quantum mechanics, and avoiding the formation of impurities in materials.

How does studying absolute zero contribute to our understanding of the universe?

Studying absolute zero can help scientists understand fundamental concepts such as thermodynamics, quantum mechanics, and the behavior of matter at different temperatures. It also contributes to our understanding of the origins and evolution of the universe.

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