A research group at Yokohama National University has succeeded in transferring quantum states from photons to carbon isotopes in diamonds without leaking information by applying the principle of quantum teleportation.
Information and communication using current technology is at risk of eavesdropping and information leakage.Therefore, in recent years, the development of quantum cryptography communication, which enables absolutely secure communication that cannot be eavesdropped, is progressing.
At present, the distance that quantum cryptography communication is possible is about 100 km.In order to make this into a large-scale network, a quantum repeater that extends the distance of quantum cryptography communication is required.
This research group devised a method to apply the principle of quantum teleportation to quantum transfer from photons suitable for long-distance transmission to quantum memory suitable for long-term storage, which is indispensable for quantum repeaters.This method consists of the following three steps.
XNUMX) Tangle is generated between the electron at the center of the nitrogen vacancy (NV center) in diamond and the nucleon of the carbon isotope in the vicinity.
XNUMX) Measure the entanglement between photons and electrons.
XNUMX) If the result of XNUMX is "yes", it means that the transfer from the photon to the carbon was successful (the quantum state of the photon is transferred to the carbon that was previously entangled with the electron by the principle of teleportation). ..
Since only the entanglement of electrons and photons is measured via electrons, it is possible to transfer without destroying the quantum state, and even if the result of the entanglement measurement is leaked, the quantum state cannot be specified from it. No leaks occur.In addition, it is said that the number of carbon used as a quantum memory can be controlled by isotope control technology, and the capacity of the quantum memory can be increased as needed.
The research group succeeded in demonstrating the experiment of this method and paved the way for networking of quantum cryptography communication by quantum relay.In the future, it is expected that it will lead to the realization of an absolutely secure and large-scale quantum Internet that connects a large number of devices that handle quantum information by quantum cryptography communication.
Paper information:[Communications Physics] Quantum teleportation-based state transfer of photon polarization into a carbon spin in diamond
