Study of Novel Quantum Phenomena in Helium Confined in Nano-Structures

纳米结构中限制的氦中新量子现象的研究

• 批准号: 16204028
• 负责人: SHIRAHAMA Keiya
• 金额: $ 29.7万
• 依托单位: Keio University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 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-16204028/
• 关键词: Helium; Superfluidity; Quantum Phase Transition; Bose System; Quantum Fluid; Quantum Solid; Supersolid; Nanoporous Material; ボース・アインシュタイン凝縮

This research project was planned to study and search for various novel quantum phenomena in helium (^4He) confined in nanoporous structures. The project involves mainly five subjects. The outcome are as follows:1. ^4He in nano-porous glass : (A) The liquid-solid phase boundary was determined by isochoric pressure measurements. We have discovered a peak in heat capacity of confined ^4He at much higher temperatures than the superfluid transition temperature. The heat capacity peak definitely shows the formation of localized Bose-Einstein condensates in nanopores. (B) We developed a new simultaneous measurement technique of torsional oscillator and ultrasound. By this technique we have found that the superfluid transition temperature is independent of frequency, but has a strong porous sample dependence. (C) We have succeeded to control the pore size of the nanoporous glass by preplating a few atomic layers of Krypton atoms. The superfluid transition temperature decreases after preplatin … More g, indicating that the decrease of the effective pore size suppress superfluidity.2. Search for quantum effects in hydrogen (H_2) in nanoporous glasses : Aiming at searching for BEC and superfluidity in molecular hydrogen, we have studied the pore size dependence of supercooling of liquid H_2 by isochoric pressure measurements. We have found that the majority of supercooled H_2 solidify at around 9 K. However, a small amount of H_2, probably confined in narrowest pores, remains liquid down to about 7 K in 2.5-nm porous glass. This indicates that BEC can be observed by confining H_2 in uniform pores narrower than 2.5 nm.3. Superfluidity of ^4He in one-dimensional nanopores: Torsional oscillator studies for ^4He in 1D nanopores in FSM-16 revealed that superfluidity is dramatically suppressed by pressurizing liquid, with Tc reaching 0 K at around 2 Mpa. This is second example of quantum superfluid transition of confined ^4He.4. ^4He in regular 3D pore structure : Torsional oscillator and pressure experiments are underway.5. Supersolid studies of ^4He : We have conducted torsional oscillator experiments for bulk solid ^4He and solid in nano porous glasses. The former study revealed strong dependence of supersolid behaviors on sample history. Less

该研究项目计划研究和寻找限制在纳米多孔结构中的氦 (^4He) 中的各种新颖的量子现象。该项目主要涉及五个课题。研究结果如下： 1． ^4He 在纳米多孔玻璃中：(A) 通过等容压测量确定液-固相边界。我们发现受限 ^4He 的热容量在比超流体转变温度高得多的温度下出现峰值。热容峰明确表明纳米孔中局部玻色-爱因斯坦凝聚体的形成。 (B) 我们开发了一种新的扭转振荡器和超声波同步测量技术。通过这种技术，我们发现超流体转变温度与频率无关，但具有很强的多孔样品依赖性。 (C) 我们通过预镀几个氪原子原子层成功地控制了纳米多孔玻璃的孔径。预铂后超流转变温度降低... More g，表明有效孔径的减小抑制了超流性。2．寻找纳米多孔玻璃中氢（H_2）的量子效应：为了寻找氢分子中的BEC和超流性，我们通过等容压测量研究了液体H_2过冷的孔径依赖性。我们发现大部分过冷的H_2在9 K左右凝固。然而，少量的H_2可能限制在最窄的孔隙中，在2.5 nm多孔玻璃中直到7 K左右仍保持液态。这表明通过将H_2限制在小于2.5 nm的均匀孔隙中可以观察到BEC。3。一维纳米孔中 ^4He 的超流性：FSM-16 中一维纳米孔中 ^4He 的扭转振荡器研究表明，超流性受到液体加压的显着抑制，Tc 在 2 Mpa 左右达到 0 K。这是受限^4He.4 量子超流体跃迁的第二个例子。 ^4He 具有规则的 3D 孔隙结构：扭转振荡器和压力实验正在进行中。5。 ^4He 的超固体研究：我们对块状固体^4He 和纳米多孔玻璃中的固体进行了扭转振荡器实验。前一项研究揭示了超固体行为对样本历史的强烈依赖性。较少的

项目成果

4^He in Nano-Porous Media : Superfluidity and Quantum Phase Transition

纳米多孔介质中的 4^He：超流性和量子相变

• 发表时间: 2007
• 期刊: J.Low Temp.Phys. 146(Invited Paper)
• 作者: K. Shimizu;T. Gotohda;T. Matsushita N. Wada;W. Fujita;K. Awaga;Y. Saiga;and D. S. Hirashima;藤原裕也;K. Hicks et al. (15番目);H.Tamura;Masanori Harada and Masaru Tsukada;T.Nakano;H.Saito;K.Shirahama
• 通讯作者: K.Shirahama

Suppression of Freezing and Emergence of a Novel Ordered State in 4^He Confined in a Nano-porous Material

纳米多孔材料中限制的 4^He 中冻结的抑制和新型有序态的出现

• 发表时间: 2006
• 期刊: Proceedings of the 24th International Conference on Low Temp.Phys.(LT24), AIP Conference Proceedings Series 850
• 作者: K.Yamamoto;Y.Shibayama;K.Shirahama
• 通讯作者: K.Shirahama

Thermodynamic Evidence for Nanoscale Bose-Einsteir Condensation in ^4He Confined in Nanoporous Media

纳米多孔介质中^4He 中纳米级玻色-爱因斯坦凝聚的热力学证据

• 发表时间: 2008
• 期刊: Physical Review Letters Vol. 100(in press)
• 作者: Keiichi;Yamamoto;Yoshiyuki;Shibayama;Keiya;Shirahama
• 通讯作者: Shirahama

Superfluidity of 4He Confined in Nano-Porous Media

纳米多孔介质中 4He 的超流性

• 发表时间: 2008
• 期刊: Low Temperature Physics (Fizika Nizkikh Temperatur), (Special Issue: Helium 100 years) 34
• 作者: *K. Shirahama;K. Yamamoto;Y. Shibayama
• 通讯作者: Y. Shibayama

ナノ多孔体に閉じこめたヘリウム4の量子相転移

限制在纳米多孔材料中的 He-4 的量子相变

• 发表时间: 2006
• 期刊: 固体物理 41
• 作者: 白濱圭也;山本恵一;柴山義行
• 通讯作者: 柴山義行