Dynamically protected qubit based on high-impedance superconducting circuits

Quantum information encoded in a physical system is submitted to decoherence induced by interaction with uncontrolled degrees of freedom in the environment of the system. However, these interactions are local in the sense that they only induce continuous evolutions of the system in its phase space. One can thus protect quantum information by storing it “non-locally”, i.e. in the correlations between distant phase space regions. Here, we propose to combine a high impedance superconducting resonator with a Josephson junction whose energy is stroboscopically modulated. This system simulates the dynamics of a LC oscillator combined with a Josephson junction and a Quantum Phase Slip element. In presence of these two non-locally acting noiseless elements, the ground states are degenerate non-local grid states of the resonator and are expected to provide a fully protected logical qubit.