Quantum phase transition of liquid helium in aerogel

气凝胶中液氦的量子相变

• 批准号: 16540312
• 负责人: MATSUMOTO Koichi
• 金额: $ 2.3万
• 依托单位: Kanazawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540312/
• 关键词: helium; superfluidity; ultrasound; aerogel; phase transition

We have presented evidence for quantum phase transition (QPT) on superfluid phase transition of helium 3 in 98% aerogel in 1997. However, the details of the QPT are not known so far. We studied the QPT of helium in aerogel for both helium 3 and 4 using ultrasound technique.1. helium 4 and aerogel systemQPT is reported for helium 4 in porous glass with small pore. We have studied superfluid transition of helium 4 in aerogel with porosity between 92 and 97 %. The transition was suppressed by aerogel. We have made the phase diagram for this system. However, QPT was not observed in aerogel. We have observed many interesting phenomena in this research. For example, anomalous sound attenuation was observed with 97 % porous aerogel around 1.7 K. This result suggested possibility of mode conversion between first, second sound in superfluid and aerogel sound mode in this composite system.Solidification of helium in aerogel was studied. Sound transmission trough the solid-liquid interface has been observed. Our experiment shows the crystal growth is suppressed by silica strands of aerogel.2. helium3 and aerogel systemA nuclear demagnetizing refrigerator has been constructed for this experiment. The sound cell has acoustic cavities with aerogel and bulk liquid for comparison. The signal with aerogel has been observed using longitudinal ultrasound at 6 MHz. Because of the trouble of refrigerator, only preliminary experimental data was obtained. The experiment is ongoing.

1997年，我们在98%的气凝胶中发现了氦3超流相变的量子相变（QPT）证据。然而，QPT的细节到目前为止还不清楚。我们利用超声波技术研究了气凝胶中氦3和氦4的QPT.本文报道了氦4气凝胶体系中氦4在多孔玻璃中的QPT。我们研究了氦4在孔隙率为92 - 97%的气凝胶中的超流转变。气凝胶抑制了这种转变。绘制了该体系的相图。然而，在气凝胶中没有观察到QPT。在这项研究中，我们观察到许多有趣的现象。例如，在1.7K附近，观察到97%多孔气凝胶的异常声衰减.这一结果表明，在该复合体系中，气凝胶声模式与超流中的一阶、二阶声模式之间可能存在模式转换。观察到声通过固液界面的传播。我们的实验表明，气凝胶的二氧化硅链抑制了晶体的生长. He~3和气凝胶系统为该实验建造了一台核退磁制冷机。声室具有声学腔，气凝胶和散装液体用于比较。气凝胶的信号已经使用纵向超声在6 MHz下观察到。由于制冷机的故障，只能得到初步的实验数据。实验正在进行中。

项目成果

Porosity dependence of sound propagation in liquid 4He filled aerogel

液体 4He 填充气凝胶中声音传播的孔隙率依赖性

• 发表时间: 2004
• 期刊: JETP Lett 80
• 作者: K.Matsumoto;Y.Matsuyama;D.A.Tayurskii;K.Tajiri
• 通讯作者: K.Tajiri

Satoshi Abe, Haruhiko Suzuki; and Dmitrii Tayurskii Possible Sound Mode Conversion in "Superfluid 4He-97% Open Aerogel" System

Satoshi%20Abe,%20Haruhiko%20Suzuki;%20and%20Dmitrii%20Tayurskii%20Possible%20Sound%20Mode%20Conversion%20in%20"Superfluid%204He-97%%20Open%20Aerogel"%20System

• 发表时间: 2007
• 期刊: Journal of Low Temperature Physics
• 影响因子: 2
• 作者: Koichi Matsumoto;Hiroyuki Tsuboya;Keiichi Yoshino
• 通讯作者: Keiichi Yoshino

Superfluid transition and solidification of 4He in aeroael

4He在航空中的超流转变和凝固

• 发表时间: 2005
• 期刊: Journal of Physics and Chemistry of Solids 66
• 作者: Koichi Matsumoto;Masaaki Nishikawa;Keiichi Yoshino;Satoshi Abe;Haruhiko Suzuki;Dimitrii A. Tayurskii;Koji Tajiri
• 通讯作者: Koji Tajiri

Possible Sound Mode Conversion in "Superfluid 4He-97% Open Aerogel" System

可能%20声音%20模式%20转换%20in%20"超流体%204He-97%%20打开%20气凝胶"%20系统

• 发表时间: 2007
• 期刊: Journal of Low Temperature Physics (印刷中)
• 作者: K.Matsumoto;H.Tsuboya;K.Yoshino;S.Abe;H.Suzuki;D.Tayurskii
• 通讯作者: D.Tayurskii

Porosity dependence of sound propagation in liquid 4He filled aeroael

声音在液体 4He 填充空气中传播的孔隙率依赖性

• 发表时间: 2004
• 期刊: JETP Lett vol 80. No.2
• 作者: K.Matsumoto;Y.Matsuyama;D.A.Tayurskii;K.Tajiri
• 通讯作者: K.Tajiri