Fast and high-fidelity coupler switching between Kerr-cat qubits using fast-forward displacement

Fast-forward scaling theory (FFST) reveals a nontrivial scaling property in quantum systems and provides a systematic method for determining system parameters that enable accelerated dynamics. We propose a scheme for transitionless displacement of a superconducting resonator with unit fidelity by combining the fast-forward and time-scaling techniques. The developed scheme is applied to achieve fast and high-fidelity switching of a coupler between Kerr parametric oscillators, which serve as Kerr-cat qubits. We evaluate the performance of the proposed parameter schedule by numerically simulating the system dynamics.