基于测量的利用原子核自旋量子比特快速生成大规模格林伯格-霍恩-泽林格态
Fast measurement-based generation of large-scale Greenberger-Horne-Zeilinger state with atomic nuclear-spin qubits
AI总结：
研究利用类碱土原子核自旋量子比特，通过量子铁磁门基于测量快速制备大规模GHZ态，从三数据原子与一辅助原子积态出发，经特定电路可生成多比特GHZ态，分析显示可实现243量子比特态且保真度高。
AI中文摘要：
大规模格林伯格-霍恩-泽林格（GHZ）态对量子技术有用但难以制备。本文提出通过一个四量子比特量子相位门，利用类碱土原子的核自旋量子比特基于测量快速制备大规模GHZ态，该门因类似于经典磁体中分子磁矩排列被称为量子铁磁门（QFG）。高保真里德堡介导的QFG可在$6\pi/\Omega_{\text{m}}$时间内实现。从三个数据原子和一个辅助原子的积态出发，通过含一个QFG、两个单量子比特门和辅助原子投影测量的粘合电路可生成3量子比特GHZ态，重复该电路可生成更多比特的GHZ态。基于现有技术分析表明可实现243量子比特GHZ态，更多比特纠缠时检测保真度更高。
英文摘要：
Large-scale Greenberger-Horne-Zeilinger~(GHZ) state is useful for quantum technologies but difficult to be prepared. Here, we propose fast measurement-based preparation of large-scale GHZ states by a four-qubit quantum phase gate with nuclear-spin qubits of alkaline-earth-like atoms, which is named as quantum ferromagnetic gate~(QFG) due to its analogy to the alignment of molecular magnetic moments in a classical magnet. A high-fidelity Rydberg-mediated QFG can be realized in a time of $6π/Ω_{\text{m}}$ with $Ω_{\text{m}}$ the maximal Rydberg Rabi frequency. From a product state of three data atom and one ancilla atom, a gluing circuit with one QFG, two single-qubit gates, and a projective measurement of the ancilla can generate a 3-qubit GHZ state, and repetition of this gluing circuit can lead to 9, 27, 81, 243, $\cdots$-qubit GHZ states. Analyses based on currently available techniques show that a 243-qubit GHZ state is realizable, and more qubits can be entangled with higher detection fidelity.
