Towards practical quantum computers: transmon qubit with a lifetime approaching 0.5 milliseconds

Abstract Here we report a breakthrough in the fabrication of a long lifetime transmon qubit. We use tantalum films as the base superconductor. By using a dry etching process, we obtained transmon qubits with a best T 1 lifetime of 503 μs. As a comparison, we also fabricated transmon qubits with other popular materials, including niobium and aluminum, under the same design and fabrication processes. After characterizing their coherence properties, we found that qubits prepared with tantalum films have the best performance. Since the dry etching process is stable and highly anisotropic, it is much more suitable for fabricating complex scalable quantum circuits, when compared to wet etching. As a result, the…

• NS
  National Science Foundation

  Award: Z190012
• NN
  National Natural Science Foundation of China

  Awards: 11890704, No. 11890704, 12004042
• NK
  National Key Research and Development Program of China

  Award: 2016YFA0301800