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Correlated Phases in Novel Superconductors and Ultracold Atomic Gases

新型超导体和超冷原子气体的相关相

基本信息

批准号：
EP/H00369X/2
负责人：
Meera Parish
金额：
$ 46.87万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2011
资助国家：
英国
起止时间：
2011 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FH00369X%2F2
关键词：
Correlated Phases Novel Superconductors Ultracold

项目摘要

The treatment of electrons as non-interacting and wave-like has yielded an amazingly successful quantum description of materials like metals and semiconductors, which form the basis of the electronics that we take for granted today. The success of this picture is all the more remarkable when one considers the size of the Coulomb interaction between the negatively-charged electrons - one only has to experience static electricity in order to appreciate the measurable effects that a small imbalance of charge can have. Thus, it is perhaps no surprise that physicists are increasingly discovering strongly-correlated systems where simple, non-interacting theories are no longer valid. A prime example is the superconductor, in which electrons form pairs at low temperatures and then flow without any resistance. Indeed, an electrical current in a superconductor can, in principle, flow forever. While this pairing phenomenon is well understood in many superconducting materials, new classes of superconductors have emerged in recent decades that are generally associated with magnetism and which superconduct at much higher temperatures than predicted by conventional theory. Clearly, developing a proper understanding of these strongly-correlated materials is more than just an esoteric pursuit: the possibility of lossless electrical current at room temperature would have a major impact on energy efficiency. The formidable challenge for the theorist is to develop fresh concepts that go beyond the current weakly-interacting descriptions. One small step in this direction is to first tackle simple versions of strongly-correlated phenomena. Fortunately, physicists now have the technological capacity to manipulate and control cold gases of atoms that have been trapped by light and magnetic fields, and thus these systems provide the ideal environment in which to study simple models. Already, I have been heavily involved in developing theories of strongly-interacting atomic superfluids , which can be regarded as neutral analogues of superconductors. The ultimate advantage of these systems is the ability to address each variable, e.g. interaction strength, one at a time and thus isolate the basic physics underlying strongly-correlated phenomena. Ideally one needs a programme of interdisciplinary theoretical research that considers unconventional superconductors in parallel with models of atomic gases, and this is the nature of the proposed research. As well as exploring model systems of superfluidity and magnetism in cold atomic gases, I aim to investigate the iron-based superconductor, a newly-discovered class of high-temperature superconductor that promises to shed light on other novel superconductors. The key idea is that the study of simple engineered atomic systems can lend insight into the iron-based superconductors, while the puzzles of unconventional superconductors can direct my research on correlated phenomena in atomic gases. This, together with input from the experiments in each highly active field, would hopefully bring us closer to a more complete understanding of interacting systems.

将电子视为非相互作用和波状的处理已经产生了对金属和半导体等材料的惊人成功的量子描述，这些材料构成了我们今天认为理所当然的电子学的基础。当人们考虑到带负电的电子之间的库仑相互作用的大小时，这张图的成功就显得更加引人注目——人们只需经历静电就能体会到微小的电荷不平衡可能产生的可测量的影响。因此，物理学家越来越多地发现强相关系统，在这些系统中，简单的、非相互作用的理论不再有效，这也许并不奇怪。一个典型的例子是超导体，其中电子在低温下形成对，然后在没有任何阻力的情况下流动。事实上，原则上，超导体中的电流可以永远流动。虽然这种配对现象在许多超导材料中得到了很好的理解，但近几十年来出现了新型超导体，它们通常与磁性有关，并且在比传统理论预测的温度高得多的温度下超导。显然，对这些强相关材料的正确理解不仅仅是一个深奥的追求：室温下无损电流的可能性将对能源效率产生重大影响。理论家面临的巨大挑战是开发超越当前弱相互作用描述的新概念。朝这个方向迈出的一小步是首先解决强相关现象的简单版本。幸运的是，物理学家现在拥有操纵和控制被光和磁场捕获的冷原子气体的技术能力，因此这些系统为研究简单模型提供了理想的环境。我已经积极参与强相互作用原子超流体理论的发展，它可以被视为超导体的中性类似物。这些系统的最终优势是能够处理每个变量，例如相互作用强度，一次一个，从而隔离强相关现象背后的基本物理。理想情况下，我们需要一个跨学科理论研究计划，将非常规超导体与原子气体模型并行考虑，这就是拟议研究的本质。除了探索冷原子气体中的超流性和磁性模型系统外，我的目标还在于研究铁基超导体，这是一种新发现的高温超导体，有望为其他新型超导体带来启发。关键思想是，对简单工程原子系统的研究可以深入了解铁基超导体，而非常规超导体的难题可以指导我对原子气体中相关现象的研究。这与每个高度活跃领域的实验输入一起，有望使我们更接近对交互系统的更全面的理解。