arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1908.10879cond-mat.supr-concond-mat.str-el
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非平衡超导体中Higgs介导的光放大

Higgs-mediated optical amplification in a non-equilibrium superconductor

Michele Buzzi, Gregor Jotzu, Andrea Cavalleri, J. Ignacio Cirac, Eugene A. Demler, Bertrand I. Halperin, Mikhail D. Lukin, Tao Shi, Yao Wang, Daniel Podolsky

摘要:

对量子材料中新功能的探索最近已经扩展到非平衡态,这是有趣的,因为它们表现出新的物理现象,并因为它们在高速器件应用中的潜力。在亚稳相的产生和外部周期驱动下的Floquet工程方面取得了显着的进展。在非平衡超导的背景下,例子包括在热力学转变温度以上产生瞬态超导,激发相干希格斯模式振荡,以及铜酸盐中层间相的光学控制。在这里,我们从理论上提出了一种新的非平衡现象,通过这种现象,从金属到瞬态超导态的迅速淬火可以引起大的序参量振幅的振荡。我们认为,这种振荡模式可以作为一个源的入射辐射的参数放大。我们报告的实验结果与这些预测是一致的光驱动K $_3$ C $_{60}$。发现当激发的开始变得慢于希格斯模式周期时,这种效应消失,与这里提出的理论一致。这些结果为在多体系统中使用集体模式来诱导非线性光学效应开辟了新的可能性。

英文摘要:

The quest for new functionalities in quantum materials has recently been extended to non-equilibrium states, which are interesting both because they exhibit new physical phenomena and because of their potential for high-speed device applications. Notable advances have been made in the creation of metastable phases and in Floquet engineering under external periodic driving. In the context of non-equilibrium superconductivity, examples have included the generation of transient superconductivity above the thermodynamic transition temperature, the excitation of coherent Higgs mode oscillations, and the optical control of the interlayer phase in cuprates. Here, we propose theoretically a novel non-equilibrium phenomenon, through which a prompt quench from a metal to a transient superconducting state could induce large oscillations of the order parameter amplitude. We argue that this oscillating mode could act as a source of parametric amplification of the incident radiation. We report experimental results on optically driven K$_3$C$_{60}$ that are consistent with these predictions. The effect is found to disappear when the onset of the excitation becomes slower than the Higgs mode period, consistent with the theory proposed here. These results open new possibilities for the use of collective modes in many-body systems to induce non-linear optical effects.

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