Scientists Make Quantum Computer Operations 1,000 Times Faster

Researchers at Chalmers University of Technology in Sweden have developed a method that can perform a broad range of advanced quantum computing operations more than 1,000 times faster than before. The theoretical study, led by Lei Du, a researcher in Applied Quantum Physics at Chalmers, is published in the journal Physical Review Letters.

Quantum computers remain highly vulnerable to errors from their surroundings, such as electrical noise, cosmic radiation and overheating. The longer a quantum operation takes to complete, the more time there is for such errors to build up and cause the computation to fail. The fundamental building blocks of quantum computers, called qubits, are so sensitive that even the smallest disturbance can cause a quantum state to deviate from its target.

To make quantum computing more resilient, the Chalmers team worked with bosonic quantum codes, which store quantum information in microwave fields inside superconducting circuits rather than in individual qubits, offering stronger protection against certain errors. Creating and controlling these quantum states had traditionally required guiding a quantum system through thousands of repeated driving cycles, each one an added opportunity for outside disturbances to interfere. The new method, built around what the team calls quantum lattice gates, can complete a wide variety of these operations within a single driving cycle instead.

Tangyou Huang, a Chalmers researcher and co-author of the study, compared the approach to building a Lego castle: rather than assembling it brick by brick, quantum lattice gates act like pre-built modules that connect quickly. The technique is designed for superconducting quantum computers, the technology Chalmers is also using to build a 100-qubit quantum computer. The researchers say they are already discussing possible experimental demonstrations of the method with colleagues at Chalmers.