An interdisciplinary team at the Advanced Quantum Testbed (AQT) at Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley's Quantum Nanoelectronics Laboratory (QNL) achieved a technical breakthrough using qutrits—three-level systems—on a superconducting quantum processor.
This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility: Technical illustration of microwave-activated two-qutrit entangling gates at fixed frequency and coupling. Credit: Noah Goss/Berkeley Lab The team successfully entangled two transmon qutrits with gate fidelities significantly higher than in previously reported works, thus getting closer to enabling ternary logic that can encode more information than their binary counterparts—qubits. Published in Nature Communications in December 2022 and featured as an editor's highlight, this experimental success pushes forward AQT's qutrit research and development, including previous experimental successes published in 2021 in Physical Review X and Physical Review Letters. Ternary quantum information processors offer significant potential advantages in quantum simulation and error correction, as well as the ability to improve certain quantum algorithms and applications. Harnessing ternary quantum information processing A superconducting qutrit, like a qubit, employs microwave-induced logical gate operations for control. However, ternary quantum logic has a more complex state space and noise environment, making single and two qutrit-logic gates in short timescales difficult to control. Recent advances in materials science and device design have improved the coherence of superconducting devices, facilitating the control of qutrits, which are generally more susceptible to noise. To fully leverage a qutrit processor's power, however, it's necessary to execute operations with high control of individual qutrits, but also entangle neighboring qutrits with high-fidelity and flexible control. Research teams have already demonstrated single qutrit operations with high fidelity. Still, entangling-gate speed has been compromised thus far by relying on a slow and static interaction that is always "on."…