受驱动耗散超导体中的迈斯纳效应与约瑟夫森辐射
Meissner Effect and Josephson Radiation in Driven Dissipative Superconductors
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中文总结 AI 辅助
本研究提出受驱动耗散超导机制解释光诱导超导特征，构建耦合序参量的连续介质理论，通过约瑟夫森结实验验证其迈斯纳效应与辐射特征，可区分非平衡与平衡超导态。
中文摘要 AI 辅助
在数种材料中，已在远高于其平衡临界温度的条件下观测到光诱导的超导特征，包括如迈斯纳效应般的磁场排斥现象。我们提出超导序参量的受驱动耗散凝聚作为该现象的一种机制：在该理论中，光泵浦会产生有效增益（可能通过参量共振实现），其可克服配对场的本征阻尼，稳定一种非平衡凝聚体，该凝聚体的相位会以本征频率旋转，该频率通常低于驱动频率且与驱动频率不可公度。我们构建了一种唯象连续介质理论，将该缓慢旋转的序参量与守恒电荷密度及电磁规范场耦合。尽管该态具有有限频率动力学，其仍展现出常规超导的长波电磁特征：在三维体系中，它呈现静态迈斯纳效应，以及由安德森-希格斯机制产生的带隙等离激元；在二维薄层中，它呈现珀尔屏蔽效应与特征平方根等离激元色散。我们进一步提出一项直接实验测试方案，基于受驱动耗散态与平衡超导体之间的约瑟夫森结：该结在零外加电压下支持交流约瑟夫森电流，并以凝聚体的本征旋转频率发射辐射，其低的、依赖泵浦且通常不可公度的频率，为区分受驱动耗散超导与平衡态、驱动锁定配对态提供了清晰特征。
英文摘要
Photo-induced superconducting signatures have been observed in several materials at temperatures far above their equilibrium critical temperatures, including magnetic field expulsion as in the Meissner effect. We propose driven-dissipative condensation of the superconducting order parameter as a mechanism for this phenomenon. In such a theory, optical pumping generates an effective gain (possibly via a parametric resonance) that overcomes the intrinsic damping of the pairing field, and stabilizes a non-equilibrium condensate whose phase rotates at an intrinsic frequency that is generally lower than, and incommensurate with, the drive frequency. We develop a phenomenological continuum theory that couples this slowly rotating order parameter to the conserved charge density and the electromagnetic gauge field. Despite its finite-frequency dynamics, the resulting state exhibits the conventional long-wavelength electromagnetic signatures of superconductivity. In three dimensions, it displays a static Meissner effect and a gapped plasmon generated by the Anderson--Higgs mechanism. In a two-dimensional sheet, it exhibits Pearl screening and the characteristic square-root plasmon dispersion. We further propose a direct experimental test based on a Josephson junction between the driven-dissipative state and an equilibrium superconductor. The junction supports an AC Josephson current at zero applied voltage and emits radiation at the intrinsic rotation frequency of the condensate. Its low, pump-dependent, and generally incommensurate frequency provides a clear signature distinguishing driven-dissipative superconductivity from equilibrium and drive-locked pairing states.
