Teleportation of Quantum Information In Diamond Is Big for Quantum Communication

Researchers from the Yokohama National University have teleported quantum information securely within the confines of a diamond which could be big for quantum computing and quantum communication.

“The success of the photon storage in the other node establishes the entanglement between two adjacent nodes,” Kosaka said. Called quantum repeaters, the process can take individual chunks of information from node to node, across the quantum field.

“Our ultimate goal is to realize scalable quantum repeaters for long-haul quantum communications and distributed quantum computers for large-scale quantum computation and metrology,” Kosaka said.

Nature Communication Physics – Quantum teleportation-based state transfer of photon polarization into a carbon spin in diamond

Quantum teleportation is a key principle for quantum information technology. It permits the transfer of quantum information into an otherwise inaccessible space, while also permitting the transfer of photon information into a quantum memory without revealing or destroying the stored quantum information. Here, we show reliable quantum state transfer of photon polarization into a carbon isotope nuclear spin coupled to a nitrogen-vacancy center in diamond based on photon-electron Bell state measurement by photon absorption. The carbon spin is first entangled with the electron spin, which is then permitted to absorb a photon into a spin-orbit correlated eigenstate. Detection of the electron after relaxation into the spin ground state allows post-selected transfer of arbitrary photon polarization into the carbon memory. The quantum state transfer scheme allows individual addressing of integrated quantum memories to realize scalable quantum repeaters for long-haul quantum communications, and distributed quantum computers for large-scale quantum computation and metrology.

Quantum teleportation is a widely used principle for quantum information technologies including quantum communication and quantum computing. Long-haul quantum communication requires quantum repeaters based on quantum teleportation to transfer a quantum bit or qubit into a distant site without revealing the qubit state. Quantum computation also requires quantum teleportation not only for one-way quantum computing but also for quantum blind computing to securely transfer input and output data via quantum communication. Finally, quantum teleportation is also in demand for the quantum storage of highly confidential data, such as DNA data, that are securely transferred by photons into quantum memories.

We have recently demonstrated the transfer of photon polarization into a nitrogen nuclear spin in a single nitrogen-vacancy (NV) center in diamond11. Delteil et al. have also demonstrated heralded absorption of a single photon color qubit in a single quantum dot. However, the stored information is limited to only one nuclear spin per one NV center or one electron spin per one quantum dot, which is a big obstacle for scaling up the memory size. On the other hand, there exist a large number of carbon isotopes (13C), which also have nuclear spins, within the reach of a nitrogen-vacancy center via a hyperfine interaction even in diamond with a natural abundance of 13C (1.1%), and the number can be increased by isotope enrichment technology. The stored qubits in carbon nuclear spins must be independent of each other and individually addressable. We have also recently demonstrated that the quantum state of isolated carbon nuclear spins weakly coupled to the NV center’s electron can be ideally maintained by the geometric spin echo based on time reversal under a zero magnetic field