Self-heating of qubit input-output lines: implications for quantum computing

At present, superconducting qubits represent a standard solution for quantum computers among academic and industrial developers alike [1,2]. In this architecture, state preparation, state manipulation and state readout are all performed using microwave transmission lines. In this talk, using measurement data combined with qubit noise models [3], we systematically assess the impact of I/O lines self-heating in cryogenic quantum computing for different attenuation schemes, qubit specifications and chip geometries. Specifically, we describe how the qubit and time-constants T₁ and T₂ are governed by the I/O thermal noise and can be limited at varying operating conditions, i.e., under different attenuation schemes, and noise spectral densities. Our results provide a useful diagnostic tool for a realistic evaluation of power versus noise trade-off in a realistic quantum computing cryogenic set-up.

[1] S. Krinner, et al., EPJ Quantum Technology (2019) 6:2

[2] Sergey Bravyi , et al., Journal of Applied Physics 132, 160902 (2022)

[3] A. Vaaranta, M. Cattaneo, and R. E. Lake, Physical Review A 106, 042605 (2022)