2026-04-14 チャルマース工科大学
A major obstacle in the development of powerful quantum computers is the growing number of cables required to control a computer as the number of qubits increases. Researchers at Chalmers University of Technology in Sweden have now demonstrated that several qubits can share the same cable – without significantly increasing computation time. Their study is the most comprehensive of its kind and could become an important piece of the puzzle in developing quantum computers. These computers have the potential to revolutionise such areas as drug development and logistics.
＜関連情報＞
- https://news.cision.com/chalmers/r/smart-cable-sharing-gives-quantum-computers-a-big-boost,c4329455
- https://journals.aps.org/prxquantum/abstract/10.1103/82cj-lfzy
時分割多重量子ビット制御を用いた量子回路におけるオーバーヘッド Overhead in Quantum Circuits with Time-Multiplexed Qubit Control
Marvin Richter, Ingrid Strandberg, Simone Gasparinetti, and Anton Frisk Kockum
PRX Quantum Published: 14 April, 2026
DOI: https://doi.org/10.1103/82cj-lfzy
Abstract
When scaling up quantum processors in a cryogenic environment, it is desirable to limit the number of qubit drive lines going into the cryostat, since fewer lines make cooling of the system more manageable and the need for complicated electronics setups is reduced. However, although time multiplexing of qubit control enables using just a few drive lines to steer many qubits, it comes with a trade-off: fewer drive lines means fewer qubits can be controlled in parallel, which leads to an overhead in the execution time for quantum algorithms. In this article, we quantify this trade-off through numerical and analytical investigations. For standard quantum processor layouts and typical gate times, we show that the trade-off is favorable for many common quantum algorithms—the number of drive lines can be significantly reduced without introducing much overhead. Specifically, we show that couplers for two-qubit gates can be grouped on common drive lines without any overhead up to a limit set by the connectivity of the qubits. For single-qubit gates, we find that the serialization overhead generally scales only logarithmically in the number of qubits sharing a drive line, and the serialization overhead relative to total quantum circuit duration tends to grow only sublinearly or stay nearly constant with the total number of qubits on the quantum processor. These results are promising for continued progress toward large-scale quantum computers.
