Complete Unitary Qutrit Control in Ultracold Atoms

Physical quantum systems are commonly composed of more than two levels and offer the capacity to encode information in higher-dimensional spaces beyond the qubit, starting with the three-level qutrit. Here, we encode neutral-atom qutrits in an ensemble of ultracold 87Rb and demonstrate arbitrary single-qutrit SU(3) gates. We generate a full set of gates using only two resonant microwave tones, including synthesizing a gate that effects a direct coupling between the two disconnected levels in the three-level A-scheme. Using two different gate sets, we implement and characterize the Walsh-Hadamard Fourier transform, and find similar final-state fidelity and purity from both approaches. This work establishes the ultracold neutral-atom qutrit as a promising platform for qutrit-based quantum information process-ing, extensions to d-dimensional qudits, and explorations in multilevel quantum state manipulations with nontrivial geometric phases.

Automated summary

In this study, neutral-atom qutrits are encoded in an ensemble of ultracold 87Rb and arbitrary single-qutrit SU(3) gates are demonstrated. The Walsh-Hadamard Fourier transform is implemented and characterized using two different gate sets, showing the potential of ultracold neutral-atom qutrits as a platform for quantum information processing.