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Search for novel mechanisms to increase the critical temperature of a superconductor

寻找提高超导体临界温度的新机制

基本信息

批准号：
EP/I004637/1
负责人：
Antonio Garcia Garcia
金额：
$ 66.49万
依托单位：
University of Cambridge
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%2FI004637%2F1
关键词：
Search novel mechanisms increase critical

项目摘要

In this proposal we investigate different aspects of superconductivity with the ultimate goal of finding novel ways - that can be tested experimentally - to increase substantially the critical temperature (Tc) of a superconductor/superfluid. Motivated by recent experimental advances in cold atom, manipulation of nanostructures and theoretical advances in high energy physics, we propose to achieve this goal by studying: 1) finite size effects in different models of high Tc superconductivity both theoretically and experimentally, 2) superconductivity in systems that do not thermalize, 3) superconductivity induced in systems with Efimov states (three particles bound states that occur in situations in which the two body interaction does not lead to bound states). In relation to 1) we aim a description, mostly analytical, of finite size effects in different mean field descriptions of high Tc superconductor. Then, for the models leading to a highest Tc's we plan to carry out a more refined theoretical analysis whose results can be used to describe superconductivity in realistic systems. Finally, in collaboration with experimentalists,we aim to chose the materials and parameters (size, grain shape...) most suitable for experimental studies, show experimentally that the critical temperature can be substantially (>15%) increased and propose technological applications. In relation to 2) we first provide a quantitative description of the stability of the equivalent of a Cooper's trimer in many body systems described by Efimov physics. Then we explore the feasibility of ground states based on a collection of Efimov states by using Monte Carlo techniques. If successful, we aim to describe quantitatively the resulting superconducting state andits stability to thermal fluctuations.In relation to 3) we first address the role of Anderson-Mott localization effects in the route to thermalization in a closed many body system by using exact diagonalization techniques, random matrix theory and the finite size scaling method. Based on these results we put forward a characterization of thermalization in closed many body systems. Finally we investigate superconductivity in systems that do not thermalize. Specifically we aim to identify the non-thermal quasiparticle distribution that enhances Tc the most.A fully theoretical/analytical descritption of these systems is challenging since many of them are strongly interacting. In high energy physics the Anti de Sitter (AdS) - conformal field theory (CFT) correspondence, provides, in certain cases a theoretical framework to tackle these problems. In relation with this problem we explore to what extent this technique provides a really quantitative description of quantum critical points and certain aspects of high temperature superconductivity.

在这个提议中，我们研究了超导性的不同方面，最终目标是找到新的方法-可以通过实验测试-来大幅提高超导体/超流体的临界温度（Tc）。受冷原子、纳米结构操纵和高能物理理论进展的最新实验进展的启发，我们建议通过研究来实现这一目标：1）理论和实验上不同高Tc超导模型中的有限尺寸效应，2）非热化系统中的超导性，3）在具有Efimov态（在两体相互作用不导致束缚态的情况下发生的三个粒子束缚态）的系统中诱导的超导性。关于1），我们的目标是描述，主要是分析，在不同的平均场描述的高Tc超导体的有限尺寸效应。然后，对于导致最高Tc的模型，我们计划进行更精细的理论分析，其结果可用于描述现实系统中的超导性。最后，与实验人员合作，我们的目标是选择材料和参数（尺寸，晶粒形状......）最适合于实验研究，实验表明临界温度可以大大提高（>15%），并提出了技术应用。关于2），我们首先提供了一个定量的描述的稳定性等效的库珀的三聚体在许多身体系统所描述的Efimov物理。然后，我们探索的基础上收集的Efimov状态，通过使用Monte Carlo技术的基态的可行性。如果成功的话，我们的目标是定量地描述所得到的超导态及其对热涨落的稳定性.对于3），我们首先利用精确对角化技术，随机矩阵理论和有限尺寸标度方法讨论了Anderson-Mott局域化效应在封闭多体系统中的热化过程中的作用。在此基础上提出了封闭多体系统热化的一个特征。最后，我们研究了不热化的系统中的超导性。具体来说，我们的目标是确定非热准粒子分布，提高Tc的most.A完全的理论/解析描述这些系统是具有挑战性的，因为它们中的许多是强相互作用.在高能物理中，反德西特（AdS）-共形场论（CFT）对应在某些情况下提供了解决这些问题的理论框架。与此相关的问题，我们探讨在何种程度上这种技术提供了一个真正的量子临界点和高温超导的某些方面的定量描述。