Strong spin-orbit interactions make hole quantum dots central to the quest for electrical spin qubit manipulation enabling fast, low-power, scalable quantum computation. Yet it is important to establish to what extent spin-orbit coupling exposes qubits to electrical noise, facilitating decoherence. Here, taking Ge as an example, we show that group IV gate-defined hole spin qubits generically exhibit optimal operation points, defined by the top gate electric field, at which they are both fast and long-lived: the dephasing rate vanishes to first order in the electric field noise along with all directions in space, the electron dipole spin resonance strength is maximized, while relaxation is drastically reduced at small magnetic fields. The existence of optimal operation points is traced to group IV crystal symmetry and properties of the Rashba spin-orbit interaction unique to spin-3/2 systems. Our results overturn the conventional wisdom that fast operation implies reduced lifetimes and suggest group IV hole spin qubits as ideal platforms for ultra-fast, highly coherent scalable quantum computing.

强大的自旋轨道相互作用使空穴量子点成为对电子自旋量子位操纵的追求的中心，从而实现了快速，低功耗，可扩展的量子计算。然而，重要的是要确定自旋轨道耦合在多大程度上使量子位暴露于电噪声中，从而促进了退相干。在这里，以Ge为例，我们表明IV组门定义的空穴自旋量子位通常表现出最佳的工作点，该点由顶栅电场定义，在该点上它们既快速又长寿：移相速率逐渐消失在电场噪声沿空间的所有方向排列的过程中，电子偶极子自旋共振强度最大，而在小磁场下，弛豫则大大降低。最佳工作点的存在可以追溯到IV组晶体的对称性和自旋3/2系统特有的Rashba自旋轨道相互作用的性质。我们的结果推翻了传统观念，即快速运行意味着寿命缩短，并建议IV组空穴自旋量子位元是超快速，高度相干的可伸缩量子计算的理想平台。