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arXiv 2103.13847physics.atom-phquant-ph
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双电子中性原子核自旋Rydberg量子计算

Rydberg quantum computation with nuclear spins in two-electron neutral atoms

Xiao-Feng Shi

摘要:

具有两个价电子和非零核自旋的类碱土~(AEL)原子可以被激发到里德堡态,用于量子计算。典型的AEL基态没有超精细分裂,但不幸的是,GHZ尺度的分裂似乎是Rydberg激发所必需的。虽然强磁场可以引起GHz尺度的分裂,但为了避免实验中的噪声,需要弱磁场。在这里,我们提供了两个解决方案,这一突出的挑战与现实的数据,充分研究的AEL同位素。在第一个理论中,两个核自旋量子比特态$|0\rangle$和$|1\rangle$分别在失谐量为$Δ$和0时被激发到里德堡态$|r\rangle$,其中MHz尺度的失谐量$Δ$来自1~G量级的弱磁场。当$Δ$和$Ω$的比例适当时,量子比特态$|1\rangle$可以被完全激发到里德堡态,而$|0\rangle$保持在里德堡态.在第二个理论中,我们证明了通过选择适当的中间态,双光子里德伯激发可以在只有一个核自旋量子比特态的情况下进行。无论磁场大小如何,第二个理论都是适用的。这些理论结合了里德堡封锁的广泛适用性和两电子中性原子核自旋量子存储的无可比拟的优势,为量子计算带来了一种通用的手段。

英文摘要:

Alkaline-earth-like~(AEL) atoms with two valence electrons and a nonzero nuclear spin can be excited to Rydberg state for quantum computing. Typical AEL ground states possess no hyperfine splitting, but unfortunately a GHz-scale splitting seems necessary for Rydberg excitation. Though strong magnetic fields can induce a GHz-scale splitting, weak fields are desirable to avoid noise in experiments. Here, we provide two solutions to this outstanding challenge with realistic data of well-studied AEL isotopes. In the first theory, the two nuclear spin qubit states $|0\rangle$ and $|1\rangle$ are excited to Rydberg states $|r\rangle$ with detuning $Δ$ and 0, respectively, where a MHz-scale detuning $Δ$ arises from a weak magnetic field on the order of 1~G. With a proper ratio between $Δ$ and $Ω$, the qubit state $|1\rangle$ can be fully excited to the Rydberg state while $|0\rangle$ remains there. In the second theory, we show that by choosing appropriate intermediate states a two-photon Rydberg excitation can proceed with only one nuclear spin qubit state. The second theory is applicable whatever the magnitude of the magnetic field is. These theories bring a versatile means for quantum computation by combining the broad applicability of Rydberg blockade and the incomparable advantages of nuclear-spin quantum memory in two-electron neutral atoms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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