Coupling a qubit coherently to an ensemble is the basis for collective quantum memories. A single driven electron in a quantum dot can deterministically excite low-energy collective modes of a nuclear spin ensemble in the presence of lattice strain. We propose to gate a quantum state transfer between this central electron and these low-energy excitations - spin waves - in the presence of a strong magnetic field, where the nuclear coherence time is long. We develop a microscopic theory capable of calculating the exact time evolution of the strained electron-nuclear system. With this, we evaluate the operation of quantum state storage and show that fidelities up to 90% can be reached with a modest nuclear polarization of only 50%. These findings demonstrate that strain-enabled nuclear spin waves are a highly suitable candidate for quantum memory.
Denning, E. V., Gangloff, D. A., Atatüre, M., Mørk, J., & Le Gall, C. (2019). Collective Quantum Memory Activated by a Driven Central Spin. Physical Review Letters, 123(14), . https://doi.org/10.1103/physrevlett.123.140502