Multimode storage of quantum microwave fields in electron spins over 100 ms

Understand

A long-lived multi-mode qubit register is an enabling technology for modular quantum computing architectures.

• For interfacing with superconducting qubits, such a quantum memory should be able to store incoming quantum microwave fields at the single-photon level for long periods of time, and retrieve them on-demand.
• Here, we demonstrate the partial absorption of a train of weak microwave fields in an ensemble of bismuth donor spins in silicon, their storage for 100 ms, and their retrieval, using a Hahn-echo-like protocol.
• The long storage time is obtained by biasing the bismuth donors at a clock transition.