Highly efficient microwave memory using a superconducting artificial chiral atom

A microwave memory using a superconducting artificial chiral atom embedded in a one-dimensional open transmission line is theoretically investigated. By applying a coupling field to a single artificial atom, we modify its dispersion, resulting in a slow probe pulse similar to electromagnetically induced transparency. The single atom's intrinsic chirality, along with optimal control of the coupling field, enables a storage efficiency exceeding 99% and near-unity fidelity across a broad range of pulse durations. Our scheme provides a feasible pathway toward highly efficient quantum information processing in superconducting circuits.