Highly-efficient multimode superconducting integrated quantum memory

Fault-tolerant quantum computing and quantum internet require quantum memory as an essential building block of a future quantum information processing platform. Superconducting circuits quantum electrodynamics (cQED) is among the leading realizations of noisy intermediate-scale quantum computers. Meanwhile there is a strong motivation to break the wall of nearest-neighbor qubit coupling using enhanced cQED architecture with integrated quantum memory. Compared with traditional superconducting qubits, high-quality factor resonators have a superior potential for quantum state storage due to their long lifetime efficient thermalization, no extra fridge control lines and ability to couple multiple qubits. We experimentally demonstrate microwave quantum storage for two spectral modes of microwave radiation in on-chip system of eight coplanar superconducting resonators. Single mode storage shows a power efficiency of up to 60±3% at single photon energy and more than 75±8% at higher intensity. The noiseless character of the storage is confirmed by coherent state quantum process tomography.