Bose-Einstein condensation at room temperature succeeded
Forecast confirmed by Albert EinsteinRead out
An international team of scientists has for the first time generated a super-quantum state of magnetic waves, a so-called Bose-Einstein condensate, without cooling at room temperature. The physicists report in the current issue of the scientific journal Nature about their study, with which they could confirm a prediction of Albert Einstein.
The so-called Bose-Einstein condensation describes a new state of matter in which all atoms lose their independence and vibrate in unison - like a single quantum object - in a common mode. This "super atom" is one of the most fascinating phenomena in physics, as the quantum nature of matter clearly stands out here. It is named after Satyendra Nath Bose and Albert Einstein, who predicted the phenomenon more than 80 years ago.
However, the Bose-Einstein condensation occurs only under very specific conditions: the density of the particles must exceed a critical value. Although Einstein was convinced that this would have to be achieved even at typical ambient temperatures, the Bose-Einstein condensation has so far been achieved only at very low temperatures near absolute zero. Because of the difficulty of producing ultra-low temperatures, the creation of a Bose superatom was one of the greatest challenges of modern experimental physics in the last century.
Only in 2001 was the experimental observation of a Bose-Einstein condensation in extremely ultra-cold, diluted alkaline gases awarded the Nobel Prize in Physics. It has since seemed utterly impossible to observe Bose-Einstein condensation of atoms at room temperature because the required atomic densities at room temperature immediately lead to the formation of liquids or solids.
However, not only atoms can show this condensation. Gases of magnetic quanta in solids, called magnon gases, are very similar to atomic gases and already exist at room temperature. However, they can not easily be put into the state of Bose-Einstein condensation because the required magnon density can not be achieved exactly as with the atomic gas. display
Laser beam as a sensor
Physicist Professor Sergej Demokritov of the Institute of Applied Physics of the Westfälische Wilhelms-Universität Münster, however, has now, in collaboration with colleagues from the University of Kaiserslautern and researchers in the USA and Ukraine, managed to overcome this obstacle on the way to a Bose-Einstein condensate Room temperature to overcome. With the help of microwaves, they generated additional magnons and mixed them with the existing magnons.
Although the additional magnons only exist for one millionth of a second, this time was enough for the scientists to study the behavior of the magnetic super gas with a laser beam as a measuring sensor.
Thus, the scientists in M nster, who are working on their work in the "Center for Nonlinear Science" of the EMU, successfully show that the collective quantum state is reached at room temperature, as Albert Einstein predicted: a magnetic Bose-Einstein condensate without any cooling.
(idw - University of M nster, 02.10.2006 - DLO)