论文标题
非高斯波动器在甜点上的高阶Qubit Dephasing：对称性打破和浮力保护
High-Order Qubit Dephasing at Sweet Spots by Non-Gaussian Fluctuators: Symmetry Breaking and Floquet Protection
论文作者
论文摘要
尽管在量子脱碳的研究中广泛采用了高斯噪声假设，但在许多量子器中都发现了非高斯噪声源，尤其是强烈的离散波动。进一步理解和减轻非高斯噪声的独特破坏作用仍然是一项重要任务。在这里，我们研究了由非高斯波动者引起的量子，并预测了非高斯噪声所特有的对称性效应。这种损坏的对称性导致在驱动率和量子频率的极端点之间进行实验可测量的不匹配，这需要在表征噪声和定位最佳工作点时要格外小心。为了进一步增强最佳位置的连贯性时间，我们建议通过Floquet Engineering抑制量子频率的二阶导数。我们使用重量磁通量的模拟显示，即使包括驱动器引入的噪声，dephasing时间的数量级也有所改善。
Although the Gaussian-noise assumption is widely adopted in the study of qubit decoherence, non-Gaussian noise sources, especially the strong discrete fluctuators, have been detected in many qubits. It remains an important task to further understand and mitigate the distinctive decoherence effect of the non-Gaussian noise. Here, we study the qubit dephasing caused by the non-Gaussian fluctuators, and predict a symmetry-breaking effect that is unique to the non-Gaussian noise. This broken symmetry results in an experimentally measurable mismatch between the extremum points of the dephasing rate and qubit frequency, which demands extra carefulness in characterizing the noise and locating the optimal working point. To further enhance the coherence time at the sweet spot, we propose to suppress the second-order derivative of the qubit frequency by the Floquet engineering. Our simulation with a heavy fluxonium shows an order of magnitude improvement of the dephasing time, even after including the noise introduced by the drive.
