Enhanced Bose–Einstein condensation and kinetic energy of liquid 4He near a free surface
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چکیده
We present neutron scattering measurements of Bose–Einstein condensation (BEC) in liquid 4He adsorbed in thick layers on an MgO substrate to study whether the condensate fraction, n0, is increased near a free surface of liquid 4He. The data show that there is definitely a condensate in the layers adsorbed on the substrate with a condensate fraction comparable to that of bulk liquid 4He. Two methods of analysis are employed to cross-check the results. The data indicate that the condensate fraction increases significantly when the number of adsorbed layers is reduced. This effect is independent of the analysis technique used. In addition, a significant increase in the kinetic energy of the 4He atoms is observed when the number of adsorbed layers is reduced.
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تاریخ انتشار 2004