| Project/Area Number |
06402013
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
物性一般(含基礎論)
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
SATOH Takeo Tohoku Univ.Institute of Science, Prof., 大学院・理学研究科, 教授 (00004424)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAGI Takeo Fukui Univ.Dept of Engineering, Lecturer, 工学部, 講師 (00206723)
NOZUE Yasuo Tohoku Univ.Institute of Science, Research Associate, 大学院・理学研究科, 助手 (60125630)
TAKAGI Shin Tohoku Univ.Institute of Science, Associate Prof., 大学院・理学研究科, 助教授 (90124594)
滝川 昇 東北大学, 理学部, 助教授 (00125600)
山口 晃 東北大学, 理学部, 教授 (60004470)
|
|---|
| Project Period (FY) |
1994 – 1996
|
| Project Status |
Completed (Fiscal Year 1996)
|
| Budget Amount *help |
¥36,100,000 (Direct Cost: ¥36,100,000)
Fiscal Year 1996: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1995: ¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1994: ¥27,000,000 (Direct Cost: ¥27,000,000)
|
|---|
| Keywords | Quantum Nucleation / Macroscopic Quantum Phenomena / ^3He-^4He Liquid Mixtures / First Order Phase Transition / 一時相転移 / 核形成 / 1次相転移 / 量子トンネル現象 |
|---|
| Research Abstract |
Quantum nucleation is a kind of macroscopic quantum tunneling phenomena, accompanying the decay of metastable system described with a macroscopic variable. The concept of quantum nucleation is currently used in varioious fields of physics. So it is extremely important to obtain the corroborative evidence of the phenomenon.
We made the first systematic studies of the low temperature phase-separation kinetics, down to 0.4mK in the two-component metastable system as a supersaturated liquid^3He-^4He mixture of dilute phase. The experiments determined the values of critical supersaturation, DELTAchi3, cr, as a function of temperature from 0.4mK up to 160mK.Here, DELTAchi3, cr, is the upperlimit of the deviation of ^3He concentration of dilute phase from the equilibrium value. The values of DELTAchi3, cr, becomes almost independent of temperature below about 10mK.This fact strongly suggests that the phase-separation is triggered by quantum nucleation, at least in this temperature region.
Another interesting feature of our results is that DELTAchi3, cr, increases with temperature above about 10mK.This conflicts with a simple expectation of the crossover consideration from the quantum to the classical regime. Such behavior may qualitatively be understood by taking into account the effect of dissipation on the tunneling probability.
In theoretical side, we re-examined the Lifshitz-Kagan model of macroscopic quantum nucleation. It is shown that the R dependence of the moss has a profound effect on the nucleation rate. Here, R is radius of the virtual nucleus. We gave a sketch to deduce the Lifshitz-Kagan model from a generalized non-linear Schrodinger field model.
|
