Junko TANIGUCHI (谷口 淳子)

Offer Organization: -, System Name: -, Category: -, Fund Type: competitive_research_funding, Overall Grant Amount: - (direct: 3200000, indirect: 960000)
本研究の目的は,１次元極限近傍の超流動の臨界速度を調べることによって,１次元系特有の量子揺らぎの効果,および素励起について知見を得ることである．具体的には,１次元性を強く（孔径を細く）した際に超流動流が消失していく過程から，１次元系特有の量子揺らぎの効果を明らかにする．さらに，臨界速度と分散関係との対応から，擬１次元ヘリウム系における素励起の励起エネルギーについての知見を得る．

Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: -, Overall Grant Amount: - (direct: 3500000, indirect: 1050000)
In the system of one-dimensional (1D) 4He, a dynamical superfluid response is expected to appear. Our purpose is to clarify how the superfluid specific to 1D becomes prominent. First, we studied the channel diameter dependence of superfluid response. When the channel diameter is reduced from 2.8 to 2.5 nm, the superfluid grows gradually with decreasing temperature, differently from the rather rapid rise for 2.8 nm. In the narrower channel, thermal activation of phase slip occurs at the lower temperature, which breaks the superfluid coherence at the lower temperature than the onset of dynamical one.
We also studied the dilute limit that the dynamical superfluid response appears for 2.8 nm channel. We found that under the unsaturated vapor pressure, a dilute liquid exists in the channel and shows a dynamical superfluid response with a large frequency dependence. We succeeded in explaining the superfluid response from dilute to pressurized liquid by the TL liquid model.

Offer Organization: -, System Name: -, Category: -, Fund Type: competitive_research_funding, Overall Grant Amount: - (direct: 3500000, indirect: 1050000)
申請者はこれまでに１次元ナノ細孔中に閉じ込めた液体4Heの超流動を２重ねじれ振子を用いて２つの異なる観測周波数で測定した．この周波数依存は，細孔中の超流動応答が１次元特有の量子揺らぎに起因する動的な現象であることを示唆している．一方，理論的な研究から１次元ナノ細孔中の液体4Heは，朝永‐らっティンジャー（TL）液体として振る舞い，その特徴として散逸ピークの温度Tpの観測周波数に対する冪的依存性が予測されている．
本研究課題は，TL液体の特徴である観測周波数に対する冪的依存性を指標として，１次元ナノ細孔の孔径と１次元性の関係を明らかにすることを目的としている．