增益调控的Transmon
The Gain-Engineered Transmon
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中文总结 AI 辅助
本研究在标准Transmon-读出谐振器电路中仅添加单频微波信号，实现了噪声偏置量子比特，其弛豫时间较|g⟩-|e⟩编码提升一个数量级，可兼容高保真快速操作，为硬件高效量子纠错提供新路径。
中文摘要 AI 辅助
量子比特与其环境的相互作用可被调控至某一误差通道主导其他通道，形成噪声偏置。该特性使量子纠错码可聚焦于主导误差类型，从而大幅减少容错量子计算所需的物理系统数量。然而，调控噪声偏置通常会在物理系统层面引入复杂性，限制可扩展性，降低其实用性。本研究在最常见的超导架构之一——标准Transmon-读出谐振器电路中，仅通过添加单频微波信号，引入并实验实现了一种噪声偏置量子比特。我们将量子比特编码于Transmon的|g⟩和|f⟩态，并调控出频率选择性增益通道，以抵消计算态间的单光子损耗误差。实验显示，与|g⟩-|e⟩编码相比，该编码的弛豫时间提升了一个数量级，仅回波相干时间下降了2倍。此外，我们证明该量子比特可兼容快速、高保真度的操作。本研究结果为将该系统作为硬件高效型量子误差检测与纠错方案的简单构建模块开辟了道路。
英文摘要
The interaction between a qubit and its environment can be engineered such that one error channel dominates over all others, resulting in noise bias. This property enables error correction codes to focus on the dominant error type, thereby significantly reducing the number of physical systems required for fault-tolerant quantum computation. However, engineering noise bias typically introduces complexity at the physical system level, which decreases its usefulness by limiting scalability. Here, we introduce and experimentally realize a noise-biased qubit in a standard transmon-readout resonator circuit, one of the most common superconducting architectures, by only adding a single microwave tone. We encode the qubit in the transmon $|\mathrm{g}\rangle$- and $|\mathrm{f}\rangle$-states, and engineer a frequency-selective gain channel that counteracts single-photon loss errors between the computational states. We demonstrate an order-of-magnitude enhancement in relaxation time compared to the $|\mathrm{g}\rangle-|\mathrm{e}\rangle$ encoding, conceding only a factor-of-two decrease in the echo-coherence time. Furthermore, we show that this qubit is compatible with fast, high-fidelity operations. Our results open a path towards using this system as a simple building-block for hardware-efficient quantum error detection and correction schemes.
