One-order-of-magnitude relaxation-time enhancement in a transmon with engineered dissipation (part 2)

Quantum error correction (QEC) protocols typically encode information redundantly across many physical qubits resulting in increased hardware overhead. Qubits with strong engineered noise bias offer an alternative that reduces the complexity of the system [1,2]. However, they typically require complex circuit designs and often involve significant tradeoffs between noise bias and operational fidelity. In this work, we enhance the relaxation time of a standard superconducting transmon qubit coupled to a readout cavity by using engineered dissipation. We activate this dissipation with a single pump tone, effectively converting cavity decay into a stabilizing process for the new qubit excited state. As compared to the standard encoding based on Fock states 0 and 1, we extend the relaxation time by more than an order of magnitude. Crucially, this improvement is achieved while maintaining fast, high-fidelity gate operations. Due to its simplicity, our approach is compatible with common experimental setups.

This talk is part two of a two-part talk.



[1] Bonilla-Ataides J. P. et al. Nat. Commun. 12, 2172 (2021)

[2] Tuckett, D. K. et al. Phys. Rev. Lett. 120, 050505 (2018)