High-spin magnetic molecules are promising candidates for quantum information processing because their intrinsic multiplicity facilitates information storage and computational operations. However, due to the absence of suitable sublevel splittings, their susceptibility to environmental disturbances and limitation from the selection rule, the arbitrary control of the quantum state of a molecular electron multiplet has not been realized. Here, we exploit the photoexcited triplet of C₇₀ as a molecular electron spin qutrit with pulsed electron paramagnetic resonance. We prepared the system into 3-level superposition states characteristic of a qutrit and validated them by the tomography of their density matrices. To further elucidate the coherence of the operation and the nature of the system as a qutrit, we demonstrated the quantum phase interference in the superposition. The interference pattern is further interpreted as a map of possible evolution paths in the space of phase factors, representing the quantum nature of the 3-level system.

高自旋磁性分子是量子信息处理的有希望的候选者，因为它们的固有多样性有助于信息存储和计算操作。然而，由于缺乏合适的亚水平分裂，它们对环境干扰的敏感性以及选择规则的限制，尚未实现对分子电子多重峰的量子态的任意控制。在这里，我们利用C ₇₀的光激发三重态作为具有脉冲电子顺磁共振的分子电子自旋量子态。我们将系统准备为qutrit的3级叠加状态，并通过其密度矩阵的层析成像对其进行了验证。为了进一步阐明操作的一致性和系统作为qutrit的性质，我们演示了叠加中的量子相位干涉。干涉图被进一步解释为相位因子空间中可能演化路径的映射，代表了三能级系统的量子性质。