Critical behavior of a trapped interacting Bose gas.
The phase transition of Bose-Einstein condensation was studied in the critical regime, where fluctuations extend far beyond the length scale of thermal de Broglie waves. We used matter-wave interference to measure the correlation length of these critical fluctuations as a function of temperature. Observations of the diverging behavior of the correlation length above the critical temperature enabled us to determine the critical exponent of the correlation length for a trapped, weakly interacting Bose gas to be nu = 0.67 +/- 0.13. This measurement has direct implications for the understanding of second-order phase transitions.
Donner
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T
Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, CH-8093 Zürich, Switzerland.
Ritter
S
S
Bourdel
T
T
Ottl
A
A
Köhl
M
M
Esslinger
T
T