Study of quantum fluid by structures in Raman spectra

通过拉曼光谱中的结构研究量子流体

• 批准号: 59420011
• 负责人: OHBAYASHI Kohji
• 金额: $ 22.98万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1984
• 资助国家: 日本
• 起止时间: 1984 至 1985
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59420011/
• 关键词: quantum fluid; superfluidity; Raman scattering; 素励起

The purpose of this research is to cralify the microscopic state of the superfluid helium 4 by the observation of laser Raman spectra. Fine structures have been found in the Raman spectra of the superfluid helium under saturated vapor pressure. However, the statistical accuracy of the data was not accurate enough to discuss the functional form in detail. Thus we developped a multi-channel spectrometer and succeeded in increasing accuracies remarkably. With this spectrometer, we re-confirmed the spectral structures of the superfluid helium under saturated vapor pressure at 1.3 K. Next, we measured the pressure dependence of the spectra by controlling the pressures to be 1,3,5,6,10,15, and 20 kg/ <cm^2> .The spectra are characterized by apprearance of three peaks <p_1> , and <p_3> . The fine structures are observed in the energy shift region between <p_1> and <p_2> . Mainly three new aspects have been found: 1) <p_2> splits into two peaks near the pressure of 5 kg/ <cm^2> .2) <p_3> , new … More ly found in this work, becomes clear as the pressure is increased. 3) The fine structures are clearly seen under the pressure up to 10 kg/ <cm^2> . The spectral shape of the fine structures cannot be explained by theories so far proposed. We further extended measurements of the two-roton peak <p_1> with higher accuracies. The peak position has been found to show a pressure dependence different from that of the two-roton energy determined by the neutron scattering. We made comparisons of the experimental spectral shapes with the theoretical model calculations so far believed to be correct, choosing the peak position and the spectral width as the adjustable parameters. We found non negligible discrepancies between them. In the higher energy side of the peak, fine structures are observed. The structure has been found to depend on the applied pressure sensitively. Considering above mentioned new aspects, we calim the spectral structures is a powerful tool to clarify the microscopic condensate state of superfluid helium 4. Less

本研究的目的是通过激光拉曼光谱的观察来明确超流氦 4 的微观状态。在饱和蒸气压下超流氦的拉曼光谱中发现了精细结构。然而，数据的统计准确性不够准确，无法详细讨论函数形式。因此，我们开发了多通道光谱仪并成功地显着提高了精度。利用该光谱仪，我们重新确认了超流氦在1.3 K饱和蒸气压下的光谱结构。接下来，我们通过控制压力为1、3、5、6、10、15和20 kg/ <cm^2>来测量光谱的压力依赖性。光谱通过出现三个峰<p_1>和<p_3>来表征。在 <p_1> 和 <p_2> 之间的能量转移区域观察到精细结构。主要发现了三个新方面：1）<p_2>在压力接近5 kg/<cm^2>时分裂成两个峰。2）<p_3>是这项工作中新发现的，随着压力的增加而变得清晰。 3) 在高达10 kg/ <cm^2> 的压力下，精细结构清晰可见。迄今为止提出的理论无法解释精细结构的光谱形状。我们进一步以更高的精度扩展了双转子峰 <p_1> 的测量。已发现峰值位置表现出与由中子散射确定的双转子能量不同的压力依赖性。我们将实验光谱形状与迄今为止认为正确的理论模型计算进行了比较，选择峰值位置和光谱宽度作为可调参数。我们发现它们之间存在不可忽略的差异。在峰的较高能量侧，观察到精细结构。已发现该结构敏感地依赖于所施加的压力。考虑到上述新的方面，我们校准的光谱结构是阐明超流氦4的微观凝聚态的有力工具。更少

项目成果

Buturi. 40 - 10. (1985)

布图里。

Physical Review B. 31-3. (1985)

物理评论 B.31-3。

日本物理学会誌. 40-10. (1985)

日本物理学会杂志40-10（1985）。