We analyse the implementation of a fast nonadiabatic CZ gate between two transmon qubits with tuneable coupling. The gate control method is based on a theory of dynamical invariants which leads to reduced leakage and robustness against decoherence. The gate is based on a description of the resonance between the ∣11⟩ and ∣20⟩ using an effective Hamiltonian with the 6 lowest energy states. A modification of the invariants method allows us to take into account the higher-order perturbative corrections of this effective model. This enables a gate fidelity several orders of magnitude higher than other quasiadiabatic protocols, with gate times that approach the theoretical limit.
@article{arxiv.2205.06555,
title = {Quantum control of tunable-coupling transmons using dynamical invariants of motion},
author = {Hilario Espinós and Iván Panadero and Juan José García-Ripoll and Erik Torrontegui},
journal= {arXiv preprint arXiv:2205.06555},
year = {2022}
}