发表机构
Centre for Quantum Technologies, National University of Singapore; Department of Physics, National University of Singapore（新加坡国立大学量子技术中心; 新加坡国立大学物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种在电路QED架构中通过单音驱动增强transmon与双腔耦合非线性，直接实现CROT门的方法，保留码无关性和错误传播特性，并验证了其在不同RSB码纠错中的有效性。
AI 中文摘要
玻色子纠错为受保护量子比特提供了一条硬件高效的途径，以实现精确的量子信息处理。对于旋转对称玻色子（RSB）码（如著名的猫码）的纠错，一个关键组件是双模受控旋转（CROT）操作。CROT门因其与码无关的通用性和错误传播特性而有用。虽然CROT门原则上可以由现有的玻色子物理原语组合而成，但当组合为一系列不完美的原语操作时，这些理想特性通常会丢失。过去的工作集中于依赖特定码特征的直接实现。在这里，我们提出了一种在电路量子电动力学（circuit-QED）架构中直接实现CROT的途径，保留了其与码无关和错误传播的特性。通过驱动同时耦合到两个微波腔的transmon，我们可控地增强微波腔之间的有效非线性，从而工程化CROT门所需的双模相互作用。仅使用单一驱动频率，我们即可实现足以进行门实现的开关比，同时最小化模式畸变。我们提供了简单的解析公式，允许识别潜在的工作区域，并通过精确数值进一步细化，并在涉及同一电路中不同RSB码的纠错示例中展示了我们CROT方法的有效性。我们的CROT门为通用玻色子信息处理可用的直接双模门库增添了新成员。
英文摘要
Bosonic error correction provides a hardware-efficient route to protected qubits for accurate quantum information processing. A critical component for error correction of rotation-symmetric bosonic (RSB) codes, like the well-known cat codes, is the two-mode controlled-rotation (CROT) operation. The CROT gate is useful because of its code-agnostic generality and its error-propagation properties. While the CROT gate can in principle be composed from existing bosonic physical primitives, the desirable properties are typically lost when composed as a sequence of imperfect primitive operations. Past work has focused on direct implementations that rely on features of specific codes. Here, we present a direct route to CROT within the circuit-QED architecture that retains its code-agnostic and error-propagation characteristics. By driving a transmon simultaneously coupled to two microwave cavities, we controllably enhance the effective nonlinearities between the microwave cavities and thus engineer the necessary two-mode interaction underlying the CROT gate. Using only a single drive frequency, we can achieve an on-off ratio sufficient for gate implementation, while minimizing mode distortions. We provide simple analytical formulas that permit the identification of potential working regimes, further refined by exact numerics, and illustrate the efficacy of our CROT approach in an error-correction example involving different RSB codes within the same circuit. Our CROT gate adds to the arsenal of direct two-mode gates available for general bosonic information processing.
