| abstract |
(57) [Summary] [Problem] To provide a quantum communication method and apparatus that can be realized in a two-photon polarization state. SOLUTION: Two-photon entangled states due to polarization are sequentially generated, and each polarization state is changed according to information to be transmitted. The first photon is held by the sender and the other, entangled second photon having a polarization that is quantum mechanically correlated with it is sent to the receiver. The sender sequentially measures the polarization state of the first photon and transmits the measurement result to the receiver via the classical communication path, and the receiver receives the second photon which appears in quantum mechanical correlation with the first photon. , The polarization state of the photon is sequentially measured, and information that the sender intends to transmit is extracted from the measurement result and the measurement result transmitted from the sender. The sender and the receiver share the change in the polarization state of the first photon and the second photon, and the information that the sender tries to transmit can be extracted by repeating the classical communication between the sender and the receiver. Thus, quantum cryptography communication highly protected from eavesdropping becomes possible. |