| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
We have proposed a model free energy (called 'hyperbolic roton model') for solidification of iperfluid helium 4. Thermal and quantum nucleation of solid under static pressures were studiec based on this model. At the initial stage of solidification, the model explicitly shows that the translational symmetry breaking should arise prior to the net density change, which results in the novel critical exponents consistent with experiment. The model not only recovers roton parameters in the stable regime (from 0 bar to the melting pressure (25 bar)), but also predicts followings for meta-stable (overpressurized) regime;
(a) The superfluid will become soft against density fluctuation at roton vector, while will remain robust against long wave length density fluctuations.
(b) The roton gap will vanish at 60 bar of overpressure, at which the superfluid phase becomes unstable.
(c) The liquid near the wall of container is effectively compressed by the wall potential, and then the critical overpressure of (b) will be reduced down to 10 bar in the presence of the wall.
Balibar (ENS, Paris) invited me for new experiment in his group to observe the intrinsic solid nucleation starting from March, 2003 by these predictions. Although the nucleation was observed at 5 bar of overpressure in the presence of glass wall, which is consistent with (c) above the intrinsic solid nucleation has been not yet observed until now (August, 2003).
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