Towards Realizing a Quantum Memory for a Superconducting Qubit: Storage and Retrieval of quantum states

  1. Shiro Saito,
  2. Xiaobo Zhu,
  3. Robert Amsüss,
  4. Yuichiro Matsuzaki,
  5. Kosuke Kakuyanagi,
  6. Takaaki Shimo-Oka,
  7. Norikazu Mizuochi,
  8. Kae Nemoto,
  9. William J. Munro,
  10. and Kouichi Semba
We have built a hybrid system composed of a superconducting flux qubit (the processor) and an ensemble of nitrogen-vacancy centers in diamond (the memory) that can be directly coupled
to one another and demonstrated how information can be transferred from the flux qubit to the memory, stored and subsequently retrieved. We have established the coherence properties of the memory, and succeeded in creating an entangled state between the processor and memory, demonstrating how the entangled state’s coherence is preserved. Our results are a significant step towards using an electron spin ensemble as a quantum memory for superconducting qubits.