Theoretical investigations in superconductivity

超导是一种发生在接近绝对零度（-273C）的极低温度下的现象，在这种温度下，某些材料失去了对电流流动的所有阻力，成为完美的导体。自1911年首次被发现以来，超导性一直在为物理和材料研究界提供重大的理论和实验挑战。近年来，新型超导体以惊人的速度被发现。1986年，一项重大突破出现了，发现了一类新的材料，它们的超导温度比以前已知的要高得多。由于超导技术在现有应用中的应用和改进潜力，例如日本正在实施的高速磁悬浮列车、用于电力传输的超导电缆、用于通信的微波滤波器、工业磁体以及使用MRI（磁共振成像）进行医疗诊断，这在世界各地的科学家中动员了前所未有的活动。这些新的超导体中有许多是非常非常规的，对传统的超导理论提出了独特的困难，可能需要一个新的范例。预计这些材料的研究不仅将为如何开发新材料和改善应用性能提供指导，而且还将导致对基础科学的新见解。我进行了理论超导的研究，以进一步了解传统和非常规超导体中的这种现象。我的工作重点有三个方面：1)计算超导体的性质，与实验进行比较；2)为研究超导体的实验组提供理论支持；3)研究阐明新型超导体（如高温超导体）超导性质的新机制。本研究的主要目标之一是利用模型计算与实验相结合，对超导的潜在机制提供重要的见解。

Superconductivity is a phenomenon occurring at very low temperatures approaching absolute zero (-273C) where certain materials lose all resistance to the flow of electrical current and become perfect conductors. First discovered in 1911, superconductivity continues to provide  major theoretical and experimental challenges to the physics and materials research communities. In recent times, new classes of superconductors have been discovered at a phenomenal rate. A major breakthrough came in 1986 with the discovery of a new family of materials which superconduct at much higher temperatures than previously known. This mobilized an unprecedented activity amongst scientists around the world due to potential for applications and improvements in existing applications using superconductivity, such as the high speed MAGLEV (Magnetic Levitation) train being implemented in Japan, superconducting cables for power transmission, microwave filters for communications, industrial magnets, and medical diagnosis with MRI (Magnetic Resonance Imaging). Many of these new superconductors are highly unconventional, posing unique difficulties with the conventional theory of superconductivity, and likely will require a new paradigm. It is expected that study of these materials will not only provide guidance as to how to develop new materials and improved properties for applications, but will also lead to new insights into fundamental science. I have carried out research in theoretical superconductivity to further understanding of this phenomenon in both conventional and unconventional superconductors. The focus of my work is three-fold: 1) to calculate properties of superconductors for comparison with experiment; 2) to provide theoretical support for experimental groups studying superconductors; and 3) to study new mechanisms for elucidating the nature of superconductivity in novel exotic superconductors, such as the high temperature superconductors. One of the main goals of this research is to use model calculations in conjunction with experiment to give important insight into the underlying mechanism of superconductivity.