A team of scientists at IBM Quantum used laser annealing to selectively tune transmon qubits into the desired frequency patterns.
Superconducting quantum processors with more than 50 qubits are currently actively available and these fixed frequency transmons are attractive due to their long coherence and noise immunity. A transmon is a type of a superconducting charge qubit designed to have reduced sensitivity to charge noise.
The research team achieved a tuning precision of 18.5 MHz, without any measurable impact on quantum coherence, and envision facilitating selective annealing in this way to play a central role in fixed-frequency architectures.
Quantum physicists had recently developed a technique for Laser Annealing of Stochastically Impaired Qubits (LASIQ) to increase the collision-free yield of transmon lattices by tuning individual qubit frequencies via laser thermal annealing.
The team demonstrated the LASIQ process as a scalable method to obtain the expected laser tuning precision. In addition to the number of tuned qubits, they measured the functional parameters of multi-qubit chips for high processor performance. During the study, they explored the LASIQ scaling capabilities by tuning a 65-qubit Hummingbird processor (accessible as ibmq_manhattan). They envision that the LASIQ process will be employed as a scalable frequency tuning tool for fixed frequency transmon architectures in future generations of superconducting quantum systems. (Phys.org)
The work has been published in Science Advances.
