Quantum Effect and Dimensional Crossover in Spin Fluctuations

近年来，低维量子反铁磁性的研究取得了长足的发展。给出了一些新的实验事实，如一维和二维自旋系统中的量子自旋涨落，自旋空间和/或对称性中的维度交叉和普适性等。这些新的浪潮归功于材料研究和开发的快速增长，这使得我们有机会利用这种低D磁体的原型进行精细实验。否则，这些重要而根本的问题只在理论上是封闭的。事实上，日本在这一研究领域的悠久传统也使其成为低维磁性领域的领先者。虽然我们处于世界前沿的这个位置，但我们认为仅有国际合作或有国际机会进行讨论是不够的。我们的首要目标是把许多努力工作并取得精彩成果的年轻科学家送到国外，并有机会与外国科学家合作。首先，在大型国际中子散射研究会议期间，我们连续组织了两次研讨会。这两个讲习班非常成功，参加这些讲习班的外国嘉宾对日本青年学员所作的非常出色的介绍和他们的积极贡献表示赞赏。我们也感谢在HMI和NIST进行的合作实验中的几个新观察到的结果，这些实验为我们提供了这个项目的中子束，因为日本的JRR3中子源已经关闭了半年。这些结果包括二维反铁磁体中的量子自旋涨落和铜酸盐(S=1/2)氧化物中的量子自旋玻璃相变。

Recently, there has been tremendous development in the research field of the low dimensional quantum antiferromagnetism. Numbers of new experimental facts are presented, such as the quantum spin fluctuations in 1 dimensional (1D) and 2D spin systems, dimensional cross over and/or universality in the spin space and/or symmetry and so forth. These new waves owe to the rapid growth in the materials research and development which enables us the opportunity to make fine experiments by using the prototype such low D magnets. Otherwise, these important and fundamental issues are closed only in theoretical interests. In fact, a long tradition in this research field made Japan as the leading country in the low dimensional magnetism as well. Though we are at this position of the world front, we don't think it is enough to collaborate internationally or to have international opportunities to discuss with. It is our primary aim to send many young scientists to abroad who work hard and present fascinating results and also to have opportunities of collaborations with foreign scientists.First, we organized two sequential workshops at the time of the large scaled international conference on neutron scattering research. These two workshops were so successful that foreign guests participated to these workshops acknowledged very fine presentations by Japanese young participants and their active contributions. We also appreciate several new observations from collaborative experiments done at HMI and NIST which gave us neutron beams for this project, since Japanese neutron source of JRR3 has been turned off for a half year. These results include quantum spin fluctuations in 2D antiferromagnets and quantum spin glass transition in the cuprate (s=1/2) oxides.