Molecular spin qudits offer an attractive platform for quantum memory, combining long coherence times with rich multi-level spin structures. Terbium bis(phthalocyaninato) (TbPc2) exemplifies such systems, with demonstrated quantum control and chemical reproducibility. In hybrid quantum architectures, TbPc2 can act as the primary memory element, with semiconductor qubits providing scalable readout and coupling. Here we present a step toward such a hybrid system: using an industrially manufactured silicon metal-oxide-semiconductor (SiMOS) spin qubit to detect electronic spin transitions of an ensemble of TbPc2 molecules. The readout is based on a compact and robust protocol that applies a microwave pulse while all gate voltages defining the qubit are held at a fixed operating point. This protocol, which combines simultaneous Rapid adiabatic Passage and Spin- Selective tunneling (RPSS), enables high-contrast resonance detection and avoids repeated π-pulse recalibration common in decoupling schemes. By demonstrating ensemble detection, we establish a foundation for integrating molecular quantum memories with industrial qubit platforms and mark an important step toward single-molecule hybrid quantum technologies.
@article{arxiv.2510.10110,
title = {Hybrid Quantum Systems: Coupling Single-Molecule Magnet Qudits with Industrial Silicon Spin Qubits},
author = {Daniel Schroller and Daniel Sitter and Thomas Koch and Viktor Adam and Noah Glaeser and Clement Godfrin and Stefan Kubicek and Julien Jussot and Roger Loo and Yosuke Shimura and Danny Wan and Yaorong Chen and Mario Ruben and Kristiaan De Greve and Wolfgang Wernsdorfer},
journal= {arXiv preprint arXiv:2510.10110},
year = {2025}
}