Effects of laser-annealing on fixed-frequency superconducting qubits

As superconducting quantum processors increase in complexity, techniques to overcome constraints on frequency crowding are needed. The recently developed method of laser-annealing provides an effective post-fabrication method to adjust the frequency of superconducting qubits. Here, we present an automated laser-annealing apparatus based on conventional microscopy components and demonstrate preservation of highly coherent transmons. In addition, we perform noise spectroscopy to investigate the change in defect features, in particular, two-level system defects, after laser-annealing. Finally, we present a local heating model as well as demonstrate aging stability for laser-annealing on the wafer scale. Our work constitutes an important step toward both understanding the underlying physical mechanism and scaling up laser-annealing of superconducting qubits. Published under an exclusive license by AIP Publishing.

Automated summary

As superconducting quantum processors become more complex, it is necessary to develop techniques to overcome frequency crowding constraints. Laser-annealing, a recently developed method, offers an effective post-fabrication approach to adjust the frequency of superconducting qubits. This study presents an automated laser-annealing apparatus based on conventional microscopy components and demonstrates the preservation of highly coherent transmons. The researchers also investigate the change in defect features, particularly two-level system defects, after laser-annealing using noise spectroscopy.