Dark state preparation in a zero-field-split molecular triplet

Maria Pfahler; Andrea Donarini

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arXiv · 2610.18661

Dark state preparation in a zero-field-split molecular triplet

Maria Pfahler·Andrea Donarini

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Abstract

We propose a protocol to prepare and probe dark states in a single-molecule electron spin resonance based on atomic force microscopy (ESR-AFM), thus extending existing techniques developed to address Rabi oscillations. To this end, we simulate in analogy to atomic physics the coherent manipulation of a three-level system in the V-configuration using a multifrequency magnetic field. More specifically, we consider a neutral molecule with a zero-field-split (ZFS) first excited triplet and analyze within a pump-probe scheme the dynamics of the total triplet population. In the triplet subspace, the dark state is a coherent superposition formed by two ZFS states which does not evolve in time despite a continuous resonant driving towards the third one. We characterize the properties of this state comparing it to its fully incoherent counterpart. Within a density-matrix formalism for open systems, we then compute the expected dark state signatures both for ideal scenarios and for the realistic parameterization of ESR-AFM on pentacene.

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Maria Pfahler, Andrea Donarini. 2026-10-13. Dark state preparation in a zero-field-split molecular triplet. https://arxiv.org/abs/2610.18661

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