基于p轨道编码的锗空穴噪声鲁棒自旋轨道量子比特
Noise-Robust Spin-Orbit Qubit in Germanium Holes via p-Orbital Encoding
AI总结：
本研究提出基于平面Ge/SiGe异质结构三空穴量子点p轨道编码的自旋-p轨道量子比特，表征电荷噪声甜区，设计全电学态转移协议，利用相邻量子点库仑相互作用实现快速两量子比特纠缠门，提升量子比特噪声鲁棒性。
AI中文摘要：
锗空穴自旋量子比特因具有强自旋轨道耦合、全电学可操控性以及无谷简并性，成为半导体量子计算的领先平台。核心障碍是电荷噪声，其通过实现快速电学控制的同一自旋轨道相互作用耦合到量子比特。本研究在平面Ge/SiGe异质结构中提出三空穴量子点的新工作模式，在四带Luttinger-Kohn--Bir-Pikus框架内建模：编码于最顶部空穴p壳层的自旋-p轨道（SpO）量子比特。我们表征了静电约束和磁场参数空间中的电荷噪声 sweet spots（甜区），估计SpO量子比特的弛豫速率与单空穴自旋量子比特的相当。随后设计并优化了无需微波驱动的全电学Landau-Zener态转移协议，诱导逻辑量子比特态跃迁，且相邻量子点间的四极-四极库仑相互作用可实现通过绝热穿梭操作的快速两量子比特纠缠门。
英文摘要：
Germanium hole spin qubits are a leading platform for semiconductor quantum computation due to their strong spin-orbit coupling, all-electrical operability, and absence of valley degeneracy. A central obstacle is charge noise, which couples to the qubit through the same spin-orbit interaction that enables fast electrical control. In this work, we propose a new operational mode of a three-hole quantum dot in a planar Ge/SiGe heterostructure, modeled within a four-band Luttinger-Kohn--Bir-Pikus framework: a spin-$p$-orbital (SpO) qubit encoded in the $p$-shell of the topmost hole. We characterize charge noise sweet spots in the parameter space of electrostatic confinement and magnetic field, and estimate that relaxation rates of the SpO qubit are comparable to those of spin qubits hosted in single holes. We then design and optimize an all-electrical Landau-Zener state-transfer protocol that induces logical qubit state transitions without microwave driving, and we show that the quadrupole-quadrupole Coulomb interaction between neighboring dots enables fast two-qubit entangling gates operated by adiabatic shuttling.
