The Research Of Quantum Error Coding

The quantum information science is a new subject, which is a combination of quantum mechanics and information. It mainly makes use of microscopic particles, that base on the special properties of quantum mechanics. For example, quantum uncertainty, quantum coherence, and quantum entanglement, those can deal with some works that the communication, calculation and cryptography of classical can't complete. In recent years, some flourish progress about quantum information has been obtained in both theory and experiment, so quantum information has shown some distinguished advantages compared with classical information. It breaks the limitations of conventional communication, cryptography, and computation. This will help realize for quantum industry of 21 centuries eventually, which combine the quantum calculation technique, quantum communication technique, nanometer technique, and nanometer module manufacturing technique. For join in the 21 centuries of developed countries group, many nations have enlarged the strength of quantum information research.The quantum computer, quantum cryptography and quantum communication are the three main fields of quantum information science, in which quantum coherence plays the most important ports. The superiority of quantum information theory comes from quantum coherence. However, in the process of qubit operation, for the environment influence, the quantum coherence will inevitably decay very quickly with time, which is called quantum decoherence, an unsolvable problem in quantum information theory. It is believed that quantum decoherence will bring about quantum error, therefore, the introduce of quantum error code is required. Quantum error code just is a method which uses the state of quantum join the qubit. This can protect the qubit has no influenced by conserved, deliver and compute of quantum decoherence. Although the method of quantum code is similar as the classic code, just use redundancy in information, for improve the anti-interference ability, but the quantum code is not the simple expansion of classic code, because of some basic difficulties, for example, quantum no-cloning, measurement destroys quantum information, and quantum errors are continuous.This paper manly discusses surrounds with quantum error correction. In chapter two, we will give the basic knowledge of quantum code, for instance, quantum bit, superposition, frequently used quantum logic gates, common scheme, some foundation properties, and theory of quantum code. In chapter three, we are main discuss the three qubits bit flip code and the three qubits phase flip code base on the classic code, that do preparation for the behind research. The emphasis is in chapter four, we according to prepare of front knowledge, according to the local and outside progress of quantum code, constructed a group of five qubits to quantum error code, and design a quantum circuit of simple quantum gates. From analyzing the progress of error correction, we find that superposition is good at the type of normal regulations; effect is similar with ordinarily code, which is more in keeping with the development of quantum computer. In chapter five, we take a wide view of the development process of quantum information, aim at the progress of experiment and theory, make an outlook of the quantum coding, and put forward our research direction of later.