Experimental observation of the Bogoliubov transformation for a Bose-Eeinstein condensed gas.
Phonons with wave vector q/(planck constant) were optically imprinted into a Bose-Einstein condensate. Their momentum distribution was analyzed using Bragg spectroscopy with a high momentum transfer. The wave function of the phonons was shown to be a superposition of +q and -q free particle momentum states, in agreement with the Bogoliubov quasiparticle picture.
Vogels
J M
JM
Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Xu
K
K
Raman
C
C
Abo-Shaeer
J R
JR
Ketterle
W
W