Theoretical Research Of Quantum Information Based On Spin Chain System

It's no double that the discovery of quantum mechanics and the development of information were the epoch-making events in 20th. A combination of the two evens yields a new subject: quantum information science, which shows a notable feature different with the classical information one. The fresh science has much predominance beyond the classical one, such as the quantum parallel algorithm based on the coherence of quantum state, which has solved some unsolvable problems by the classical ways of the factorizations of large numbers; Such as the establishment of the safe absolute quantum code system, based on the quantum no-cloning theorem which forbids the quantum information be copied as the classical information. Such as the quantum teleporation due to quantum entanglement, which acts as quantum channel to join different space sites. Quantum information science open a new door for the information science, and has some ascendancy, such as safety, fast, lager capability. In a word, the birth of quantum information science brings new activity into the future information science and technology.Now, the theory of quantum information has been widely uses to every branch of physic and some as science, which has accelerated the development of information secienc and technology. Recently, physical research men has joined the institution. In one hand, they posed some notable concepts, fundamentals, methods, on the other hand, men is searching systems suitable for quantum computation, such as cavity QED, quantum dots, nuclear magnetic resonance, and so on. But every system has its own merit and defect. The spin chain system, based on the interaction of solid state system, is a system can implement quantum computation one, and has some new feature an merit in the generation of quantum entangled states, teleportation, quantum clone. Due to this facts, the spin chain system has caused much interesting recently. Here, we study the character of quantum state, teleportation, quantum clone base on spin chain system, and the main results include:(1) We study the thermal entanglement and mixture in a spin system. Solid state systems, due to the easy integration, are the promising candidates for realizing quantum computation. Vast literatures show that spin chain is one of the systems used for quantum computation and quantum communication. It is helpful to explain and find new phenomena to study the...