![]() ![]() Individual atoms can be studied there with very great accuracy and their inner structure can be determined. The laser light functions as a thick liquid, dubbed optical molasses, in which the atoms are slowed down. Phillips have developed methods of using laser light to cool gases to the µK temperature range and keeping the chilled atoms floating or captured in different kinds of “atom traps”. Steven Chu, Claude Cohen-Tannoudji, and William D. #Atoms join together to form what free#When the temperature is one-millionth of a degree from this point (termed 1 µK, microkelvin) free hydrogen atoms, for example, move at speeds of less than 1 km/hr (= 25 cm/s). Only as one approaches absolute zero (-273☌) does the speed fall greatly. But even a temperature as low as -270☌ involves speeds of about 400 km/hr. If, however, the process takes place in a vacuum the density can be kept low enough to avoid condensation and freezing. In liquids and solid bodies, study is made more difficult by the fact that single atoms and molecules get too close to one another. By lowering the temperature one can reduce the speed, but the problem is that when gases are cooled down they normally first condense into liquids and then freeze into a solid form. It is hard to study these atoms and molecules because they disappear all too quickly from the area being observed. Atoms floating in optical molassesĪt room temperature the atoms and molecules of which the air consists move in different directions at a speed of about 4,000 km/hr. Phillips, National Institute of Standards and Technology, Gaithersburg, Maryland, USA,įor development of methods to cool and trap atoms with laser light. Professor Claude Cohen-Tannoudji, Collège de France and École Normale Supérieure, Paris, France, andĭr. Professor Steven Chu, Stanford University, Stanford, California, USA, The Royal Swedish Academy of Sciences has decided to award the 1997 Nobel Prize in Physics jointly to ![]()
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