Parametric QED: from high-fidelity readout to resolving readout anomalies

Efficient readout remains a key functionality for any self-respecting quantum information processing platform. In this talk I will describe a new paradigm of parametric QED (pQED), which has enabled new functionalities for high-fidelity, tunable readout by deploying strong parametric interactions in the dispersive regime of pQED [1,2]. Next, I will discuss our recent efforts to extend open system descriptions aimed at using such platforms for reservoir engineering and how it enabled a surprising resolution of the long-standing T1 anomaly in circuit-QED [3].

[1] Z. Xiao, E. Doucet, T. Noh, L. Ranzani, R. W. Simmonds, L. C. G. Govia, A. Kamal. Perturbative diagonalization for time-dependent strong interactions, Phys. Rev. Applied 18, 024009 (2022).
[2] T. Noh, Z. Xiao, K. Cicak, X. Y. Jin, E. Doucet, J. Teufel, J. Aumentado, L. C. G. Govia, L. Ranzani, A. Kamal, R. W. Simmonds. Strong parametric dispersive shifts in a statically decoupled multi-qubit cavity QED system, Nature Physics, s41567-023-02107-2 (2023).
[3] T. Thorbeck, Z. Xiao, A. Kamal, L. C. G. Govia. Readout-induced suppression and enhancement of superconducting qubit lifetimes, arXiv:2305.10508 (2023).