A Passive $\mathcal{PT}$-Symmetric Floquet-Coupler

Passive $\mathcal{PT}$-symmetric couplers without complex optical potentials

In addition to the implementation of parity-time ($\mathcal{PT}$)-symmetric optical systems by carefully and actively controlling the gain and loss, we show that a $2\times 2$ $\mathcal{PT}$-symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive $\mathcal{PT}$-symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients. This opens up the possibility to implement general $\mathcal{PT}$-symmetric systems…

可调耦合器Transmon中的泄漏迁移与被动泄漏消除

Leakage Mobility and Passive Leakage Removal in Transmons with Tunable Couplers

通过数值和解析方法研究可调耦合器Transmon中的泄漏动力学，发现即使消除单激发交换或ZZ相互作用，泄漏跳跃率仍为0.8-10 MHz，并利用泄漏迁移提出两种被动泄漏消除单元。

Connecting active and passive $\mathcal{PT}$-symmetric Floquet modulation models

Open systems with gain, loss, or both, described by non-Hermitian Hamiltonians, have been a research frontier for the past decade. In particular, such Hamiltonians which possess parity-time ($\mathcal{PT}$) symmetry feature dynamically stable regimes of unbroken symmetry with completely real eigenspectra that are rendered into complex conjugate pairs as the strength of the non-Hermiticity increases. By subjecting a $\mathcal{PT}$-symmetric system to a periodic (Floquet) driving, the regime of dynamical stability can be dramatically affected, leading to a frequency-dependent threshold for the $…

Design and Testing of Superconducting Microwave Passive Components for Quantum Information Processing

We report on the design, fabrication and testing of two superconducting passive microwave components, a quadrature hybrid and a 20 dB directional coupler. These components are designed to be integrated with superconducting qubits or Josephson parametric amplifiers and used in quantum information processing applications. For the coupler, we measure return loss and isolation > 20 dB, and insertion loss < 0.3 dB in a 2 GHz band around 6 GHz. For the hybrid performance, we measure isolation > 20 dB and insertion loss < 0.3 dB in a 10% band around 6.5 GHz. These values are within the design specifi…

高保真集成量子光子逻辑 via 抗扰方向耦合器

High-Fidelity Integrated Quantum Photonic Logic Via Robust Directional Couplers

本研究提出一种被动几何设计策略，通过稳健方向耦合器提升量子逻辑门保真度，实现高保真集成量子光子逻辑。

在光子集成电路中使用复合分段方向耦合器实现高保真CNOT门

High fidelity CNOT gates in photonic integrated circuits using composite segmented directional couplers

本文提出了一种基于复合分段方向耦合器的高保真CNOT门设计，通过实验和模拟验证其在提升门保真度和降低误差方面的优势。