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Topological phase transition between the gap and the gapless superconducting states

发布时间:2023-11-22

讲座论坛 期数 萨本栋讲坛之150期
主题 Topological phase transition between the gap and the gapless superconducting states 演讲者 Prof. Andrey Varlamov
时间 2023年11月24日(周五) 14:30 机构 意大利国家研究委员会
地点 物理楼552

Abstract :   It is demonstrated that the quantum phase transition between the gap and gapless  superconducting states in the Abrikosov-Gor'kov theory of superconducting alloy with paramagnetic impurities is of the Lifshitz type, i.e. of the 2 1#2 order. This phase transition has a topological nature and is characterized by the corresponding change of the topological invariant, namely the Euler characteristic. We study the stability of such a transition with respect to the spatial fluctuations of the magnetic impurities critical concentration ?! and show that the requirement for validity of its mean field description is unobtrusive: ∇ ln(?!) ≪ ?"#(here ? is the superconducting coherence length). Finally, we show that, similarly to the Lifshitz point, the 2 1#2 order phase transition should be accompanied by the corresponding singularities, for instance, the superconducting thermoelectric effect has a giant peak exceeding the normal value of the Seebeck coefficient by the ratio of the Fermi energy and the superconducting gap.


主讲人简介:安德烈·瓦尔拉莫夫(Andrey Varlamov)教授是超导理论和凝聚态物理学领域的著名科学家,1980年在阿历克斯·阿布里科索夫(2003年获诺贝尔物理学奖得主)指导下获凝聚态物理学博士学位,1986年获苏联国家青年科学家物理学奖,1990~1999任莫斯科钢铁与合金研究所理论人曾兽zoomoo马app人曾兽zoomoo马app教授;1999年起任意大利国家研究委员会超导、新材料和器件研究所研究主任,罗马大学教授;2009年起任意大利科学院通讯院士;有8本超导理论方面的专著和130余篇科学论文;已有50余篇科普作品发表于《量子》等著名科普刊物,主要由这些科普作品结集成书的《奇妙的物理学》,自1987年面世以来,以6种语言出版了12版,直接影响了世界各国的科普读者。