发表机构
Lincoln Laboratory, Massachusetts Institute of Technology; Research Laboratory of Electronics, Massachusetts Institute of Technology; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology（林肯实验室，麻省理工学院; 电子研究实验室，麻省理工学院; 电气工程和计算机科学系，麻省理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究磁通量子比特中准粒子诱导耗散，通过数值分析不同情况的耗散率，发现现有模型在特定偏置点有误判。考虑超导能隙能量不对称性可抑制弛豫，光子辅助隧穿产生的QP只有特定能量才有\(T_1\)保护，为处理器开发和策略制定提供依据。
AI 中文摘要
由杂散红外和电离辐射产生的非平衡准粒子（QP）会限制超导量子处理器的性能，并给量子纠错方案带来挑战。QP诱导能量弛豫的模型通常假设QP的特征能量和量子比特跃迁能量相对于超导能隙都很小。在此假设下，某些量子比特如磁通量子在特定偏置点会免受QP诱导的耗散。我们通过数值分析不同QP能量分布和通过光子辅助隧穿过程产生的QP在磁通量子比特中预测的QP诱导耗散率，发现考虑小数值因素后，现有理论模型预测在之前认为受保护的偏置点对QP诱导误差敏感。我们发现结处超导能隙能量的不对称性可重新引入对QP诱导弛豫的抑制。此外，对于光子辅助隧穿产生的QP，我们预测只有特定能量的对破坏辐射才会出现\(T_1\)保护。这种对磁通量子对QP诱导耗散敏感性的理解为基于磁通量子的处理器开发和未来QP缓解策略提供了参考。
英文摘要
Nonequilibrium quasiparticles (QPs) generated by stray infrared and ionizing radiation can limit the performance of superconducting quantum processors and present challenges for quantum error correction schemes. Models of QP-induced energy relaxation commonly assume that the characteristic energy of the QPs and the qubit transition energy are both small relative to the superconducting gap. Under these assumptions, certain qubits such as the fluxonium would exhibit protection against QP-induced dissipation at specific bias points. Here, we show that this is not necessarily the case, numerically analyzing the predicted rate of QP-induced dissipation in fluxonium qubits for different QP energy distributions and for QPs created via photon-assisted tunneling processes. We find that accounting for small numerical factors, existing theoretical models predict sensitivity to QP-induced errors at bias points previously thought to be protected. We find that inclusion of asymmetry in the superconducting gap energy across the junction can reintroduce suppression of QP-induced relaxation, as expected. Additionally, for QPs created by photon-assisted tunneling, we predict that $T_1$ protection will only occur for a specific energy of pair-breaking radiation. This understanding of fluxonium sensitivity to QP-induced dissipation informs the development of fluxonium-based processors and future QP-mitigation strategies.
Comments9 pages, 4 figures
