Quantum Beating Induced by Subcycle Terahertz Supercurrent Driving

ORAL

Abstract

Recent studies have shown that time-periodic acceleration of superconducting condensates driven by oscillating terahertz (THz) fields generates a superfluid center-of-mass momentum that persists long after the driving pulse has passed [1,2]. An effective electromagnetic field—distinct from the bare THz field—emerges from the interplay between the applied field and the induced supercurrent. Understanding how this effective field breaks equilibrium symmetry on sub-cycle timescales and enables quantum beating between driven states is of fundamental importance. Here, we directly visualize the sub-cycle acceleration of the superconducting condensate, revealing the buildup of quantum beating within individual oscillation periods. This lightwave current acceleration mechanism provides a pathway toward sub-cycle control of dissipationless topological currents and other anomalous quantum transport phenomena.

[1] X. Yang, et al., Nature Photonics 13, 707 (2019).

[2] C. Vaswani, et al., Physical Review Letters, 124, 207003 (2020).

*The THz experiments were supported by the National Science Foundation under Award No. 2530947. The theoretical simulations were supported by the U.S. Department of Energy, Office of Basic Energy Sciences, 13 Division of Materials Sciences and Engineering. Ames National Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358. Synthesis of pnictide thin films and characterizations at University of Wisconsin-Madison was supported by the USDOE, Office of Science, Basic Energy Sciences (BES), the Materials Sciences and Engineering (MSE) Division, under award No. DE-FG02- 06ER46327. C.B.E. acknowledges support for this research through a Vannevar Bush Faculty Fellowship (ONR N00014-20-1-2844), and the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant GBMF9065.

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Presenters

  • Avinash Khatri

    • Iowa State University

Authors

  • Avinash Khatri

    • Iowa State University

  • Martin Mootz

    • Ames National Laboratory

  • Chuankun Huang

    • Iowa State University

  • Liang Luo

    • Ames National Laboratory
    • Ames National Laboratory, U.S. Department of Energy, Ames, IA 50011, USA

  • Ilias Perakis

    • University of Alabama at Birmingham

  • Chang-Beom Eom

    • University of Wisconsin - Madison
    • University of Wisconsin-Madison

  • JIGANG Wang

    • Iowa State University