Quantum technology: bringing infinite possibilities to the future world

Quantum is a collective term for elementary particles such as photons, protons, neutrons, electrons, and mesons. It is the smallest elementary particle known in the physical world. The ubiquitous light in daily life consists of a large number of light quanta. In quantum mechanics, scientists focus on the behavior and interaction of matter and energy on the scale of individual atoms or subatomic particles. Compared with the macroscopic physical world, quantum has many wonderful properties, such as quantum superposition and quantum entanglement. Among them, the most important influence on communication is "quantum entanglement." Quantum information science is the product of the combination of quantum mechanics and information science. It includes quantum cryptography, quantum communication, quantum computers, etc. In recent years, major breakthroughs have been made in theory and experiment.

　　 In the 1990s, physicists theoretically proved that for objects in the microscopic world, with the help of magical "quantum entanglement", unknown quantum states of matter can be accurately transmitted to remote locations without transmitting the matter itself. Combining quantum mechanics theory with information technology, through the precise manipulation of photons, atoms and other microscopic particles, information encoding, storage, transmission and other processing methods will undergo revolutionary changes.

　　Because the behavior of one quantum unit can instantaneously affect another quantum unit, thereby changing the state of the measured substance, this characteristic means that it is impossible to achieve an exact copy of an unknown quantum unit. Based on this principle, scientists put forward the concept of quantum cryptography, which is to use matter with a quantum state as a cryptography.

　　 Quantum cryptography uses the quantum entanglement effect to carry out confidential transmission of information. Its advantage is that there is no need to laboriously edit passwords, or even conventional passwords at all, to send the information directly in an entangled state, which can be perfectly confidential. The reason is that when a hacker breaks into the transmission network, the photon beam will be disordered, and the detector of each node will point out the increase of the error level, thereby issuing an alarm of interference; the sending and receiving parties will also randomly select and compare, and all matches will be confirmed. The information has not been tapped. In this way, hackers cannot break into a quantum system without leaving a trace, and even attempting to decode this action will cause the quantum cryptographic system to change its original state. Of course, even if a hacker successfully intercepts and obtains a decryption key for a set of password information, it is only garbled information, and while completing this action, it also leads to a change in the key. When a legitimate information receiver checks the key, it can be known from the change of the quantum state that the password has been intercepted. Once a flaw is found, it will be replaced with a new key immediately.

The emergence of quantum cryptography has brought about a brand-new change in the security of keys. Applying quantum cryptography to quantum communication system becomes quantum secure communication. With the industrialization of quantum communication technology and the realization of wide-area quantum communication networks, it will not take much time. Quantum secure communication, as a key technology to ensure communication security in the information society, will move towards large-scale applications-widely used in politics, economy, In important fields such as technology and finance, provide basic confidential services and the most reliable security guarantee for the information society.

　　 In addition to security and confidentiality, "sweeping speed" is also another major advantage of quantum communication. The algorithmic basis of traditional communication is 0 or 1, while quantum communication is a quantum unit that not only contains 0 or 1, but also a state where 0 and 1 coexist. All units can complete logical operations at the same time and complete multiple tasks at the same time. This characteristic of quantum computers is destined to greatly increase the speed of quantum communication than the current communication speed. For example, the 4G network delay time is 50 milliseconds, and the transmission of radio signals from Mars to the earth will be delayed for ten minutes. The use of quantum communication technology is not affected by the transmission distance, can eliminate the delay phenomenon, and realize "instant" communication. In the future, the advantages of instant communication with quantum communication will be very useful.

　　 Obviously, quantum properties have a unique function in the field of information. They will break through the limits of existing information systems in terms of increasing computing speed, ensuring information security, and increasing information capacity. Quantum communication can fundamentally eliminate secret theft, ensure information security, and greatly increase the speed of information processing. After the large-scale promotion and application of quantum communication, the "quantum Internet" will naturally replace the current Internet.

　　 The difficulty in the practical application of quantum information technology lies in the manipulation of multi-particle entanglement, which is also the core physical resource of quantum information processing. Scientific research has proved that to realize the basic functions of practical quantum simulators and quantum computers, at least entanglement of dozens to hundreds of qubits must be realized. At present, scientists can only entangle 12 kinds of particles at one time; and for quantum computers to achieve commercial applications, at least this number needs to be increased by tens or even hundreds of times. It seems that the phased results of quantum communication are within reach, and the decisive results need to be continued!

　　 Of course, the application of quantum theory far exceeds the fields of computing and communication, and quantum science brings infinite possibilities. As Einstein said: "What we see now is only a part of a real entity that has not been fully understood." Through quantum theory, humans will have the opportunity to build a bridge between the micro and macro worlds.

It can also manufacture a high-sensitivity gravitational intensity measuring instrument for detecting underground pipelines or detecting nuclear submarines below the deep sea. The sophisticated sensors made with advanced quantum technology can measure the activity of brain neurons, which is like a human brain controlling a computer. The goal is a big step forward.

　　 In short, the use of quantum theory to transform information technology is expected to achieve a revolutionary breakthrough in information processing capabilities. Quantum computers and quantum communications not only exist in science fiction, but are getting closer to the real world. Quantum technology will play a subversive role in promoting the progress of human social civilization. It is necessary to further innovate technologies and reform concepts to better control multi-particle entanglement, thereby promoting the development and growth of the quantum industry