|Merrill, Physics: Principles and Problems||"Very cold temperature are reached by liquefying gases. Helium liquefies 4.2 kelvin, or -269 degrees Celsius. Even colder temperatures can be reached by using the properties of special substances placed in the fields of large magnets. By using these techniques, physicists have reached temperatures of only 2.0 × 10−9 K"||2.0 nK|
|Low Temperature World Record. Low Temperature Lab, Helsinki University of Technology.||"The record-low temperature was reached in a piece of rhodium metal, which was cooled to 100 pK, or 0.000 000 000 1 degrees above the absolute zero. The absolute zero is the limit of all temperatures, -273.15 °C, a temperature one can never reach. However, at the Low Temperature Laboratory, the researchers have for more than 20 years been reaching closer and closer. The previous Low Temperature World Record of 280 pK was in fact set here in 1993."||0.10 nK
|Steven Chu, former Bell Labs researcher, wins Nobel in physics. Bell Labs Innovations.||"By this ingenious method, Chu and his colleagues managed to cool the sodium atoms to 240 millionths of a degree above absolute zero."||240,000 nK|
|"William Phillips and co-workers at NIST developed a highly efficient magnetic trap that used it to cool atoms down to 40 millionths of a degree above absolute zero in 1988. Claude Cohen-Tannoudji had contributed greatly to the theoretical understanding of cooling experiments. Between 1988 and 1995, he and his group developed a new method, using helium atoms. They managed to cool the helium atoms produced to less than a millionth of a degree over absolute zero."||40,000 nK
< 1,000 nK
|Towards the absolute zero. Low Temperature Lab, Helsinki University of Technology.||"During our present research on rhodium, the spin system has been cooled to 250 pK, the lowest temperature ever produced and measured, but no sign of magnetic ordering has been observed so far."||0.25 nK|
The limit of all temperature is absolute zero. For many years physicists have been closing in on absolute zero. No one will ever succeed in reaching it, but many have come very close. To reach a very low temperature, such gases as helium have to be liquefied and such a methods have been used by physicists in Bell Labs in Holmdel, NJ. In 1987 physicist Steven Chu, a former Bell Labs scientist, and other physicists by the names of William Phillips and Claude Cohen-Tannoudji who also worked in the same lab came up with the idea of trapping atoms with lasers by lowering the temperature during their conversation over a lunch table in the lab's cafeteria. Chu and his companions, Phillips and Cohen-Tannoudji, figured out a way to lower the atom's temperature to one ten-millionth of a Kelvin above absolute zero or 0.1 μK. In 1997, ten years after patenting the idea of trapping atoms with lasers by lowering the temperature, he honored with a Nobel Prize in physics for all his work in Bell Labs. After 20 years of constant research the Low Temperature Lab at the Helsinki University of Technology managed to reach 280 pK or 280 trillionths of a Kelvin. However, in the year 2000 that record was surpassed when a piece of rhodium metal was cooled to 100 pK or 0.000,000,000,1 degrees above absolute zero by a team of physicists at this same lab.
Nehemie Cange -- 2001