RQC Seminar

18th RQC Seminar

  • 講演者

    Prof. Stephen Hughes
    (Department of Physics, Queen’s University, Ontario, Canada ）

  • 日程

    2022年11月10日（木）16:00-17:00（JST）

  • 開催場所

    ハイブリッド（Zoom ・ 理研　和光事業所　本部棟2階 大会議室）

  • 講演タイトル

    Understanding waveguide-QED systems with time-delayed coherent feedback

  • お問合せ

    rqc_info[at]ml.riken.jp

講演概要
Waveguide-QED allows one to efficiently couple quantum emitters (e.g., quantum dots and flux qubits) via confined waveguide modes and provides a platform for harnessing the quantum coherence of light. Introducing time-delayed coherent feedback is a proposed method for improving the figures of merit for various quantum protocols. However, quantum feedback manifests in a non-Markovian dynamic that is notoriously difficult to model using traditional approaches in quantum optics (such as Markovian master equations, which fail). I will discuss and exemplify two methods to address this problem [1-4]: (i) a new quantum trajectory discretized-waveguide model, and (ii) matrix product states. These two techniques are quite different in origin, but can be complimentary, and I will highlight their main advantages and disadvantages. Several applications will be shown, including the quantum dynamics and output spectra from 1, 2 and 3 qubit systems, and the roles of off-chip photon decay and qubit pure dephasing on population trapping.

[1] Sofia Arranz Regidor, Gavin Crowder, Howard Carmichael, Stephen Hughes. Modelling quantum light-matter interactions in waveguide-QED with retardation, nonlinear interactions and a time-delayed feedback: matrix product states versus a space-discretized waveguide model, Phys. Rev. Research, 3, 023030 (2021)
[2] Gavin Crowder, Lora Ramunno, Stephen Hughes, Quantum Trajectory Theory and Simulations of Nonlinear Spectra and Multi-Photon Effects in Waveguide-QED Systems with a Time-Delayed Coherent Feedback, Phys. Rev. A 106, 013714 (2022)
[3] Sofia Arranz Regidor, Stephen Hughes, Cavity-like strong coupling in macroscopic waveguide QED using three coupled qubits in the deep non-Markovian regime, Phys. Rev. A 104, L031701 (2021)
[4] Sofia Arranz Regidor, Stephen Hughes, Probing dressed states and quantum nonlinearities in a strongly coupled three-qubit waveguide system under optical pumping, e-print: arXiv:2209.10403 (2022)

 Back to top