Quantum dynamics of few-photon pulsed waveguide-QED with a single artificial atom: frequency-dependent scattering theory and time-dependent matrix product states
Queen’s University（女王大学）
Sofia Arranz Regidor, Matthew Kozma, Stephen Hughes
We present a quantum dynamical study of pulsed few-photon scattering from a single artificial atom, consisting of a two-level system (TLS) or qubit, in a waveguide QED system, directly comparing and contrasting two different quantum theoretical simulation methods: (i) an input-output scattering approach that uses frequency-dependent scattering matrices, and (ii) a matrix product states (MPS) approach, which uses quantum noise operators in time bins and a tensor network technique to solve the time-dependent waveguide function for the entire system. Beginning with pulsed excitation using one-photon and two-photon Fock state pulses, we first show how to compute time-dependent observables with the scattering matrix approach, in terms of frequency integrals that encode the pulse spectrum, including how to extract the population dynamics of the excited quantum emitter, as well as the linear and nonlinear contributions. We present solutions for both symmetric and chiral TLS coupling. We then show how to compute the qubit and field observables in a more direct way using MPS, and obtain the characteristic bird-like shape for the two-photon correlation function at two times, which has been observed in recent experiments. We compare and contrast both of these methods, for one and two-photon excitation pulses, and show excellent agreement. We also present a study of the linear and nonlinear contributions, which can easily be calculated using scattering theory, and show the important role of pulse duration. Finally, we demonstrate the clear advantages of MPS by easily going to higher N-photon excitations, and show selected example population dynamics of up to eight-photon Fock-state pulses, manifesting in clear nonlinear population oscillations during the pulse interaction, similar to classical Rabi oscillations, but with quantum input fields that have a vanishing electric field expectation value.
Engineering protected cavity-QED interactions through pulsed dynamical decoupling
University of the Basque Country UPV/EHU（巴斯克地区大学）；Instituto de Física Teórica, UAM-CSIC, Universidad Autónoma de Madrid（马德里自治大学理论物理研究所）；Quantronics Group, SPEC, CEA Saclay, CNRS, Université Paris-Saclay（巴黎综合理工学院集团、SPEC、CEA萨克雷、CNRS、巴黎萨克雷大学）；Department of Physics, ETH Zürich（苏黎世联邦理工学院物理系）；Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften（瓦尔特·迈斯纳研究所，巴伐利亚科学院）；Technische Universität München, TUM School of Natural Sciences, Physics Department（慕尼黑工业大学自然科学学院物理系）；Munich Center for Quantum Science and Technology (MCQST)（慕尼黑量子科学与技术中心）
Photon Anomalous Blockade in Waveguide Cavity QED with Atomic Mirrors
School of integrated circuits, Tsinghua University（清华大学集成电路学院）；Beijing Automation Control Equipment Institute（北京自动化控制设备研究所）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences（中国科学院大学拓扑量子计算卓越创新中心）；Frontier Science Center for Quantum Information（量子信息前沿科学中心）
Modelling quantum light-matter interactions in waveguide-QED with retardation and a time-delayed feedback: matrix product states versus a space-discretized waveguide model
Photonic state engineering via energy-level crossing by giant atoms in topological waveguide QED setup
School of Physics Science and Technology, Shenyang Normal University（沈阳师范大学物理科学与技术学院）；School of Physical Science and Technology, Soochow University（苏州大学物理科学与技术学院）；Center for Quantum Sciences and School of Physics, Northeast Normal University（东北师范大学量子科学中心与物理学院）
Strongly-coupled non-Markovian waveguide QED with input-output HEOM
RIKEN Center for Quantum Computing, RIKEN（理化学研究所量子计算中心）；Department of Physics, National Cheng Kung University（国立成功大学物理系）；Center for Quantum Frontiers of Research and Technology (QFort)（量子前沿研究与技术中心）；Physics Division, National Center for Theoretical Sciences（国家理论科学中心物理组）；Physics Department, University of Michigan（密歇根大学物理系）
