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Nonclassical rotational inertia in helium crystals
A C Clark1, J T West, M H W Chan
1Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. acc172@psu.edu
Physical Review Letters
|October 13, 2007
Summary
Nonclassical rotational inertia (NCRI) in solid helium was investigated. The study found that NCRI is not caused by liquid helium films on grain boundaries, challenging existing theories.
Area of Science:
- Condensed matter physics
- Quantum phenomena in solids
Background:
- Nonclassical rotational inertia (NCRI) in solid helium is a puzzling phenomenon.
- A leading hypothesis attributes NCRI to the superflow of thin liquid helium films along grain boundaries.
Purpose of the Study:
- To investigate the origin of NCRI in solid helium.
- To test the validity of the superfluid grain boundary model.
Main Methods:
- Observation of NCRI in large solid helium-4 (He) crystals.
- Crystallization of He at controlled constant temperature and pressure.
Main Results:
- NCRI was observed in solid He crystals.
- The experimental results contradict the predictions of the superfluid grain boundary model.
Conclusions:
- The superfluid grain boundary model is insufficient to explain NCRI in solid helium.
- Alternative mechanisms for NCRI in solid helium require further investigation.
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