Researchers Achieve 99.61% Single-Qubit Gate Fidelity With Integrated Laser

Scaling trapped-ion quantum computers has been hindered by bulky tabletop lasers and complex optical systems. Demonstrating coherent control of strontium ions using a fully integrated photonic laser stabilised with an on-chip device is the achievement of researchers at the University of Massachusetts Amherst and the University of California Santa Barbara. Coherent control of strontium ions is key technology for quantum computing enabled by this fully integrated photonic laser system.

Current systems require bulky lasers and optics, but this work utilises a chip-based device stabilising the laser directly, paving the way for miniaturisation. High precision single- and two-qubit operations were achieved with fidelities exceeding ninety percent, extending coherence times vital for complex calculations. These results represent progress towards building more compact and strong trapped-ion quantum computers. Trapped ions function as tiny electrically charged atoms held in place by electromagnetic fields; these act as basic units of information, known as qubits, within a quantum computer.

Current systems rely on large lasers and optics, yet this team’s approach uses an on-chip device stabilising the laser directly, enabling potential miniaturisation. Precisely timed pulses of light to manipulate qubit states and coherent qubit gates were demonstrated, achieving fidelities exceeding ninety percent alongside extended coherence times akin to maintaining balance on a spinning top for longer periods. These results represent progress toward building more compact and strong trapped-ion computers, though questions remain regarding monolithic integration with ion traps and long-term stability under real-world conditions.