Quantum Disorder and Spin-Gaps In Models and Real Materials

这项资助是为了支持加州大学戴维斯分校的高级研究员/学者辛格的工作。辛格因其对受挫磁铁的研究而闻名。由于被破坏的磁体在非常低的温度下才会有序，因此在相变中偶尔会出现量子效应。在此资助期间，他计划将他的研究项目集中在三个平行的方向上。在第一种情况下，将会寻找经历量子相变的模型自旋系统。在第二种情况下，将计算各种各样的实验测量量，例如（不仅）输运和热力学响应，还包括中子散射截面和核磁共振弛豫率。这些将与各种材料的实验进行比较，如高Tc超导体，自旋阶梯和链，二维自旋间隙系统，二聚自旋系统和其他复杂和相关电子效应的例子。在第三种情况下，将继续寻求理论计算的受控和系统的数值方法。这位职业生涯中期/高级PI以其研究材料而闻名，这些材料直到非常低的温度才变得磁性。原因是原子矩发现它们被环境中的其他原子矩鼓励指向不同的方向。因此，磁铁被称为受挫磁铁，它们的性质受到它们无法有序的强烈影响。此外，它们也成为量子相变等新现象的可能候选者。这项资助的研究项目将进行有组织的研究，包括发展形式主义，计算在不同实验中测量的数量，然后与实验结果进行比较，最后开发复杂的计算工具。这是一个雄心勃勃和复杂的研究计划，有望为新颖和复杂材料的特性提供见解

This grant has been awarded to support the work of Singh, a senior researcher/scholar at UC Davis. Singh has become well known for his work on frustrated magnets. Since the frustrated magnets do not order until very low temperatures, there are occasionally quantum effects in the phase transition. In this grant period he is planning to focus his research program in three parallel directions. In the first case, there will be a search for model spin systems, which undergo quantum phase transitions. In the second case, there will be calculations of a wide variety of experimentally measured quantities such as (not only) transport and thermodynamic responses, but also including neutron scattering cross sections and NMR relaxation rates. These will be compared with experiments on a variety of materials, such as high Tc superconductors, spin ladders and chains, 2-d spin gap systems, dimerized spin systems and other examples of complex and correlated electron effects. In the third case, there will be a continued search for controlled and systematic numerical methods for theoretical calculations.%%%This midcareer/senior PI is well known for his studies of materials which do not become magnetic until very low temperatures. The reason being that the atomic moments find themselves encouraged to point in different directions by other atomic moments in the environment. The magnets then, are called frustrated and their properties are strongly influenced by their inability to order. Furthermore they also become possible candidates for novel phenomena such as quantum phase transitions. The research program in this grant will pursue an organized course of research, including development of formalism, calculation of quantities which are measured in diverse experiments and then compared with experimental results and finally development of sophisticated tools of calculation. It is an ambitious and complex plan of research which is expected to provide insight into the properties of novel and complex materials.***