AI 中文总结
本文提出一种基于远失谐光学耦合与声学调制的参数控制方案，实现量子点自旋的快速通用控制，门保真度超过99.9%，显著优于现有方法。
AI 中文摘要
量子通信、分布式计算和混合架构依赖于能够实现量子比特相干控制并耦合到传播量子模式的节点。虽然半导体量子点（QD）自旋与微波和光学光子耦合，但与机械波的弱相互作用限制了单量子点自旋量子比特集成到片上、声学耦合的混合系统中。现有的声学量子点自旋控制理论受限于旋转轴角度范围，导致门原语的实现复杂且门时间较长，几乎没有余地来抵抗三子衰变和准静态核自旋噪声引起的退相干。我们提出了参数控制来克服这些问题。我们利用与三子态的远失谐光学耦合来修饰（dress）并因此混合自旋态，同时结合光学跃迁能量的声学调制。我们不依赖于直接与自旋分裂的声学共振（这会导致显著的瓶颈），而是通过与修饰自旋分裂的共振来参数化地诱导自旋旋转。因此，我们开发了“摆动式”（swing-up）电荷态激发的自旋模拟。我们的方案提供了具有几乎任意旋转轴的快速通用量子比特控制。我们的约155皮秒Pauli-X门持续时间比之前的声光公式快约290倍，比光学法拉第几何自旋旋转快约14倍。参数方案自然支持高次谐波过程。对约44 GHz声学驱动的数值模拟显示，即使在未冷却的GaAs和InAs量子点核自旋环境中，对于三子寿命大于等于1.25纳秒的情况，平均门保真度也大于等于99.9%。这些指标表明实际可用的控制，并可能引入具有高相互作用率、多功能性和多声子过程的自旋-声子接口，这对于未来声学耦合的混合架构至关重要。
英文摘要
Quantum communication, distributed computing, and hybrid architectures rely on nodes enabling coherent control of qubits and coupling to propagating quantum modes. While semiconductor quantum-dot (QD) spins couple to microwave and optical photons, weak interaction with mechanical waves has limited the integration of single-QD spin qubits into on-chip, acoustically coupled hybrid systems. The existing theory of acoustic QD spin control suffers from a limited range of rotation-axis angles, enforcing complex realizations of gate primitives and long gate times, leaving little margin against decoherence from trion decay and quasi-static nuclear-spin noise. We propose parametric control that overcomes these problems. We use far-detuned optical coupling to a trion state to dress and thus mix spin states, combined with acoustic modulation of the optical transition energy. Instead of relying on direct acoustic resonance with the spin splitting that leads to significant bottlenecks, we induce spin rotations parametrically via resonance with the dressed-spin splitting. We thus develop a spin analog of the ``swing-up'' charge-state excitation. Our scheme provides fast universal qubit control with nearly arbitrary rotation axes. Our ${\sim}$155 ps Pauli-$X$ gate duration is ${\sim}290\times$ faster than in the previous acousto-optical formulation and ${\sim}14\times$ faster than optical Faraday-geometry spin rotation. The parametric scheme naturally enables higher-harmonic processes. Numerical simulations for ${\sim}44$ GHz acoustic driving show average gate fidelity $\ge99.9\%$ even for uncooled nuclear-spin environments of GaAs and InAs QDs for trion lifetime $\gtrsim1.25$ ns. These metrics suggest practically usable control and may introduce a spin-phonon interface with high interaction rates, versatility, and multi-phonon processes, essential for future acoustically coupled hybrid architectures.
Comments12 pages, 5 figures
