Quantum Rotor Qubits in Metal Halide Perovskites

The schemes of a single molecule for constructing quantum bits (qubits) have aroused intense interest in the field of quantum information science. Here, we propose a qubit based on the rotational motion of the organic cation in metal halide perovskites (MHPs), in which the superposition states are composed of the ground and first-excited rotational states. We study the decoherence and the damped Rabi oscillation of this qubit due to the transfer of phonon angular momentum stemming from the coupling between the rotating cation and the phonon bath. We find that the lifetime of a qubit could reach milliseconds if only considering this decoherence source, imposing the long-lifetime boundary for this type of qubit. These results not only provide a potential platform for constructing qubits in the MHPs to explore the applications in quantum information and computation but also open up avenues for studying the fundamental physics related to the transfer of phonon angular momentum.