发表机构
ETH Zurich; Harvard University; Max Planck Institute for the Physics of Complex Systems; Max Planck Institute for the Structure and Dynamics of Matter; University of Oxford; California Institute of Technology; MIT（苏黎世联邦理工学院; 哈佛大学; 马克斯·普朗克复杂系统物理研究所; 马克斯·普朗克物质结构与动力学研究所; 牛津大学; 加州理工学院; 麻省理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分析层对称与反对称驱动对相位无序超导双层膜的影响，发现仅层对称驱动能增强相对相位锁定和磁屏蔽，为驱动YBCO实验提供了对称性诊断方法。
AI 中文摘要
最近的实验表明，在强亚皮秒光学激发后，材料在其平衡转变温度以上表现出类超导特性，这激发了人们对具有周期性调制的超流刚度的相位无序超导体的理论兴趣。先前对单层光学电导率的分析表明，即使周期平均刚度保持不变，这种驱动也能增强低频$1/ω$响应。我们将这些研究扩展到双层系统，如YBa$_2$Cu$_3$O$_{6+x}$（YBCO）铜氧化物，通过考虑具有不同对称性的驱动。具体来说，我们研究了一种层对称驱动，其中两个平面同时变硬和变软，以及一种层反对称驱动，其中一个平面变硬而另一个变软。两种驱动都增强了层平均相位的相关性，并产生可比较的类超导光学电导率。然而，只有对称驱动才能加强相对相位锁定以及相关的对平行于平面的磁场的逆流响应。因此，增强的$1/ω$光学电导率本身并不意味着增强的磁屏蔽。鉴于驱动YBCO的应用，其中类超导面内光学和瞬态抗磁性均已被报道，我们的结果提供了一种对称性诊断：在相位同步机制内，实验激活的低频刚度调制必须包含实质性的层对称分量。
英文摘要
Recent experiments demonstrating superconducting-like characteristics in materials above their equilibrium transition temperatures following strong sub-picosecond optical excitation have stimulated theoretical interest in phase-disordered superconductors subject to a periodically modulated superfluid stiffness. Previous analyses of the single-layer optical conductivity have shown that such a drive can enhance the low-frequency $1/ω$ response, even when the period-averaged stiffness remains unchanged. We extend these studies to bilayer systems, such as the YBa$_2$Cu$_3$O$_{6+x}$ (YBCO) cuprate, by considering drives with different symmetries. Specifically, we investigate a layer-symmetric drive, in which the two planes stiffen and soften simultaneously, and a layer-antisymmetric drive, in which one plane stiffens while the other softens. Both drives enhance correlations of the layer-averaged phase and generate comparable superconducting-like optical conductivities. Only the symmetric drive, however, strengthens relative-phase locking and the associated counterflow response to a magnetic field parallel to the planes. Thus, an enhanced $1/ω$ optical conductivity does not by itself imply enhanced magnetic screening. In view of applications to driven YBCO, where superconducting-like in-plane optics and transient diamagnetism have both been reported, our result provides a symmetry diagnostic: within a phase-synchronization mechanism, the experimentally active low-frequency stiffness modulation must contain a substantial layer-symmetric component.
CommentsMain: 6 pages, 4 figures; Supplement: 6 pages, 6 figures
