Yokohama National University (Hideo Kosaka)
Osaka University
Nippon Telegraph and Telephone Corporation (NTT)
National Institute of Informatics (NII)
To make a practical quantum repeater, we need to have a long-lived quantum memory at the nodes. Our target is to make an interface between a photon as a transmission qubit and a nuclear spin as a memory qubit intermediated by an electron spin as a gate qubit.
Toward this purpose, we have several candidates such as semiconductor quantum dots, NV centers in diamond, and rare-earth impurities in non-linear crystal. Among those candidates this project focuses on NV centers in diamond which provide longest memory time together with reasonable optical activity.
The project consists of four groups – Yokohama national univ., Osaka univ., NTT, and NII. Each of them contributes different aspects as summarized below.
For quantum entanglement purification between remote nodes, gate operation and entanglement detection between nuclear spins intermediated by an electron spin are needed besides the quantum media conversion. Furthermore, we have to solve the issue of fidelity degradation upon the system operation when we combine the quantum media conversion, gate operation, and entanglement detection.
Main result
Team 158B-T02 results summary
Task title | Outcome | Publications |
---|---|---|
1: Hybrid quantum repeater fundamental technology | Development of quantum tomography technique based on initialization, manipulation, and readout of degenerate electron and nuclear spins in an NV center. | Phys. Rev. Lett., 114, 053603 (2015). |
Demonstration quantum state transfer from a photon to a nuclear spin via an electron spin with heralding function based on the quantum teleportation principle. | Nature Photonics,10,507-511(2016). | |
Development of geometrical spin echo technique for enabling quantum media conversion and quantum gate operation with keeping quantum memory. | Nature Communications, 7, 11668 (2016). | |
2: Hybrid quantum repeater purification technology | Realization of 105 times gate operation within quantum memory lifetime. | 28th International Conference on Defects in Semiconductors, (2015) [Invited] |
Charge stabilization of NV– center for faithful quantum non-demolition measurement towards complete Bell-state measurement. | Physical Review B, 93, 081203 (R), 2016 | |
Manipulation of three nuclear spin quantum entanglement | Appl. Phys. Lett., 106, 153103 (2015). | |
3: Hybrid gate and optical module design | Proposal of an expandable quantum repeater network with an optical module based on an NV center inside the optical cavity with optical input/output modes. | New J. Phys., vol. 17, 103012 (2015) |
Optimization of gate operations by considering the dynamics of the election and 15N & 13C nuclear spins in an NV center. | New J. Phys., Vol. 16, 093043 (2014), Phys. Rev. A 89, 052317 (2014) | |
Design of the physical properties of three different module configurations with a cavity and a single NV center. |
1. Hybrid quantum repeater fundamental technology
(Yokohama National Univ.)
2. Hybrid quantum repeater purification technology
(Osaka University)
3. Hybrid gate and optical modulede sign
(NTT & NII)
Outlook (1/2)
Outlook (2/2)