Time-division multiplexing opens path for larger quantum computers

One promising architecture for quantum computers relies on quantum charged-coupled devices (QCCDs). Similar to how classical CCDs transfer packets of charge to store and read out, the QCCD architecture shuttles trapped-ion qubits between different functional zones.

Thus far, demonstrations of QCCDs have relied on one-to-one architectures with one digital-to-analogue converter assigned to one electrode. But this quickly leads to impractical wiring scenarios as even a few tens of qubits would require hundreds of direct current control signals.

To overcome this bottleneck which limits the scalability of such quantum computers, Ohira et al. developed an alternative electronic system that uses time-division multiplexing to control many ion-trap electrodes.

Building on a previous paper, where they laid out a proof-of-concept, the researchers experimentally validated the time-division multiplexing approach to scaling up electrode control. They contained a single calcium ion in a surface-electrode trap and demonstrated ion transport.

“We are most excited that our system worked in a real ion-trap experiment,” said author Ryutaro Ohira. “Our results suggest that the wiring and hardware bottlenecks in trapped-ion quantum computing can be overcome, opening a realistic path toward much larger processors.”

The researchers plan to continue their scaling work to support more electrodes and eventually integrating multi-zone ion-trap chips.

“We hope this work will serve as a foundation for scalable control systems in next-generation trapped-ion quantum computers,” Ohira said. “The ability to reduce wiring and hardware while maintaining reliable operation means that much larger electrode arrays can be controlled with far fewer resources.”

Source: “Trapping an atomic ion using time-division multiplexed digital-to-analog converters,” by Ryutaro Ohira, Masanari Miyamoto, Shinichi Morisaka, Ippei Nakamura, Atsushi Noguchi, Utako Tanaka, and Takefumi Miyoshi, Applied Physics Letters (2025). The article can be accessed at https://doi.org/10.1063/5.0294871 .