用于自旋量子比特态转移的手性磁振子
Chiral magnons for spin-qubit state transfer
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中文总结 AI 辅助
该研究提出用手性磁振子介导远距离NV中心自旋量子比特间的态转移，通过两种耦合调制方法规避损耗，数值表明数微米距离的态转移保真度可达≥0.95，拓展了量子信息领域磁振子学的应用工具。
中文摘要 AI 辅助
我们提出了一种协议，其中手性磁振子介导两个远距离自旋量子比特之间的态转移。该协议通过随时间改变自旋量子比特与磁振子之间的耦合来实现，从而将任意态从一个量子比特转移到另一个量子比特。耦合的调制方式使得双自旋量子比特态始终保持为磁振子库的暗态，从而规避了相关损耗。我们表明，该协议可在混合系统上实现，该系统由两个氮空位（NV）中心耦合到钇铁石榴石（YIG）条带的非互易手性磁振子模式构成。我们提出两种实现NV-磁振子耦合时间调制的方法：i）改变两个NV中心的NV-磁体距离；ii）改变一个NV中心的外磁场和NV-磁体距离。我们通过数值评估了两种方法的可实现性，包括温度约束，以及实现高保真度态转移所需的自旋量子比特的退相时间和最小寿命。我们发现，使用实际实验参数，可实现相距数微米的NV中心之间的态转移，保真度≥0.95。我们的发现拓展了磁振子学在量子信息领域的应用工具箱。
英文摘要
We propose a protocol where chiral magnons mediate a state transfer between two distant spin qubits. The protocol is implemented by varying the coupling between the spin qubits and the magnons in time, such that an arbitrary state is transferred from one qubit to the other. The modulation of the coupling is performed such that the two-spin-qubit state is kept as a dark state of the magnon bath, bypassing the associated losses. We show that the protocol can be realized on a hybrid system composed of two nitrogen-vacancy (NV) centers coupled to the nonreciprocal and chiral magnon modes of an yttrium iron garnet (YIG) stripe. We propose two methods to achieve the time modulation of the NV-magnon coupling: i) the NV-magnet distance of both NV centers is varied; ii) the external magnetic field and the NV-magnet distance of one NV center are varied. We evaluate the implementability of both methods numerically, including the constraints on the temperature, and the dephasing time and minimal lifetime of the spin qubits required for high-fidelity state transfer. We find that using realistic experimental parameters, a state transfer between NV centers at a distance of several microns can be achieved with a fidelity $\gtrsim 0.95$. Our findings expand the toolbox of magnonics for quantum information purposes.
