Universal qutrit control in asymmetric-top molecules

TL;DR

This paper develops a theoretical framework for universal single-qutrit control in asymmetric-top molecules, enabling high-fidelity quantum operations through analytic pulse design and robustness analysis.

Contribution

It introduces an analytic protocol for arbitrary single-qutrit gates in asymmetric-top molecules, including a multilevel pulse-area theorem and robustness insights.

Findings

Achieved high-fidelity Walsh-Hadamard gates with minimal leakage.

Derived a multilevel pulse-area theorem for systematic control field design.

Analyzed error sensitivity depending on SU(2) decomposition strategies.

Abstract

We present a theoretical framework for universal single-qutrit control in asymmetric-top molecules, advancing molecular quantum information processing. In this approach, the qutrit is encoded in three rotational eigenstates, with an auxiliary state providing independent phase control within the computational manifold. We explore an analytic protocol for arbitrary single-qutrit gates, combining directly addressable SU(2) rotations with auxiliary-state-mediated phase operations. To support this, we derive a multilevel pulse-area theorem that provides an explicit analytic mapping between gate parameters and control fields, enabling systematic design of high-fidelity microwave pulse sequences. Numerical simulations with 1,2-propanediol confirm the robustness of our approach, achieving Walsh-Hadamard gates with minimal leakage from the computational subspace. We further examine four SU(2) decomposition strategies and find that phase-error sensitivity depends on the decomposition sequence, while amplitude errors propagate along specific coherence pathways. Our results establish asymmetric-top molecules as a viable platform for qutrit-based quantum operations and offer an analytical method for precise quantum control of complex multilevel systems.