Four-photon entangled W state-based super-dense coding method for quantum signaling

Abstract

The invention discloses a four-photon entangled W state-based super-dense coding method for quantum signaling. The problems of low signaling coding capacity, low efficiency and poor security in a quantum communication process are mainly solved. The method is implemented by a process comprising the following steps of preparing four-photon (A, B, C and D) entangled W state as the quantum signaling, and transmitting the photons C and D to a receiver by using a transmitter; performing unitary transformation on the photons A and B to obtain 16 new quantum states; forming an orthogonal basis by using the 16 new quantum states; coding the new quantum states respectively, and sequentially transmitting photons A' and B' obtained by the unitary transformation to the receiver; and after the receiver receives the photons A' and B', arbitrarily selecting a measurement basis from the orthogonal basis, and performing joint measurement on the photons A', B', C and D to measure a new quantum state to finish coding. The method has the advantages of high coding efficiency, high capacity and high security, and can be used for a signaling system for quantum mobile communication.

Description

technical field [0001] The invention belongs to the technical field of encoding, in particular to a quantum signaling ultra-dense encoding method, which can be used in quantum communication networks. Background technique [0002] Signaling is an essential and important part of any communication system, and quantum communication is no exception. In a multi-user quantum communication network, the encoding method of quantum signaling directly affects the transmission efficiency and security of the signaling system. [0003] Existing quantum coding schemes mainly include amplitude coding, frequency coding, phase coding, differential phase coding, and two-photon entanglement ultra-dense coding, three-photon entanglement controlled ultra-dense coding and four-photon entanglement controlled ultra-dense coding. in: [0004] The encoding efficiency of amplitude encoding, frequency encoding, phase encoding and differential phase encoding is relatively low, and only one bit of inform...

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Problems solved by technology

[0004] The encoding efficiency of amplitude encoding, frequency encoding, phase encoding and differential phase encoding is relatively low, and only 1 bit of information can be transmitted in one encoding

[0005] Two-photon entanglement ultra-dense coding, one coding can transmit 2 bits of classical information, however, in the process of communication between multiple users, the capacity of the signaling system is relatively large, this coding method needs to be coded multiple times to achieve It can meet the communication requirements and is relatively cumbersome;

[0006] Three-photon entanglement controlled ultra-dense coding requires a controller in addition to the receiver and sender, and the coding efficiency is mainly related to the measurement angle when the controller performs von Neumann measurements on its own photons. Because of the limitation of the angle, Therefore, the classic information transmitted by one encoding is less than 3 bits, and the encoding process is particularly cumbersome, and the encoding efficiency is relatively low;

[0007] Four-photon entanglement controlled ultra-dense coding, in addition to the receiver and the sender, there are two controllers, like the three-photon, the coding efficiency is mainly related to the measurement angle when the controller performs von Neumann measurement on its own photons, Due to the limitation of the angle, the coding efficiency of the four-photon entanglement controlled ultra-dense coding is less than 4 bits. Compared with the three-photon, the coding capacity is improved, but the coding efficiency is basically the same.

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