Figure 1. Schematic of circuit-QED design for storage and retrieval of an unknown single-and two-qubit states.

(a) A USC memory cell element, composed of a qubit-resonator system operating at the USC regime. (b) Two flying microwave photons, with modes and , come in and pass through a beam splitter (BS) implemented by a superconducting quantum interference device (SQUID) to form a two-qubit entangled state, which is then stored in two USC qubits located at a distance apart.