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Bose-Einstein condensation in solid 4He
S O Diallo1, J V Pearce, R T Azuah
1Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716-2593, USA.
Physical Review Letters
|August 7, 2007
Summary
Neutron scattering experiments in solid helium show no evidence of Bose-Einstein condensation (BEC) below the critical temperature, despite observed superfluidity. The atomic momentum distribution remains unchanged, indicating zero condensate fraction.
Area of Science:
- Condensed Matter Physics
- Quantum Fluids
Background:
- Superfluidity in solid helium suggests Bose-Einstein condensation (BEC).
- Previous observations indicate superfluid density below the critical temperature (Tc).
Purpose of the Study:
- To investigate the presence of Bose-Einstein condensation (BEC) in solid helium.
- To measure the atomic momentum distribution n(k) and determine the condensate fraction (n0).
Main Methods:
- Neutron scattering measurements were performed on solid helium.
- Experiments were conducted at 41 bar pressure and temperatures between 80 and 500 mK.
Main Results:
- The atomic momentum distribution n(k) showed no change upon crossing the critical temperature (Tc).
- Condensate fractions at 80 mK and 120 mK were found to be consistent with zero (n0 = -0.10 ± 1.20% and n0 = 0.08 ± 0.78%, respectively).
Conclusions:
- The study found no evidence for Bose-Einstein condensation (BEC) in solid helium under the tested conditions.
- The results suggest that the observed superfluidity may not be directly linked to a macroscopic occupation of the k=0 state.
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