Department of Chemistry and Institute for Sustainability and Energy at Northwestern , Northwestern University , Evanston Illinois 60208-3113 , United States.
J Am Chem Soc. 2020 Feb 19;142(7):3346-3350. doi: 10.1021/jacs.9b13398. Epub 2020 Feb 5.
Photoinduced electron transfer can produce radical pairs having two quantum entangled electron spins that can act as spin qubits in quantum information applications. Manipulation of these spin qubits requires selective addressing of each spin using microwave pulses. In this work, photogenerated spin qubit pairs are prepared within chromophore-modified DNA hairpins with varying spin qubit distances, and are probed using transient EPR spectroscopy. By performing pulse-EPR measurements on the shortest hairpin, selective addressing of each spin qubit comprising the pair is demonstrated. Furthermore, these spin qubit pairs have coherence times of more than 4 μs, which provides a comfortable time window for performing complex spin manipulations for quantum information applications. The applicability of these DNA-based photogenerated two-qubit systems is discussed in the context of quantum gate operations, specifically the controlled-NOT gate.
光诱导电子转移可以产生具有两个量子纠缠电子自旋的自由基对，这些自由基对可以作为量子信息应用中的自旋量子位。这些自旋量子位的操纵需要使用微波脉冲选择性地寻址每个自旋。在这项工作中，通过改变自旋量子位距离的发色团修饰的 DNA 发夹中制备光生自旋量子位对，并使用瞬态 EPR 光谱进行探测。通过对最短发夹进行脉冲 EPR 测量，证明了对构成对的每个自旋量子位的选择性寻址。此外，这些自旋量子位对的相干时间超过 4 μs，这为执行量子信息应用中的复杂自旋操纵提供了舒适的时间窗口。在量子门操作的背景下，特别是受控非门，讨论了这些基于 DNA 的光生双量子位系统的适用性。
