Study On The Thermal Entanglement Of Quantum Information

Quantum information science is a newly developed subject from the end of 20th century, and is a new product of the combination of quantum mechanics and information science. It can break the physical limitation of information techniques and provides new principles and methods for the scientifically development. It, through the special characters of quantum mechanics, can solve some information processing function that classical information can not. Quantum communication, including quantum teleportation, quantum dense coding, and so on, is an important part of quantum information. Quantum entanglement has been used as an important source in quantum communication by the development of quantum information and quantum computer. Entanglement, which has no corresponding one in classical physics, is a special phenomenon in quantum mechanics. As the base of quantum information, quantum entanglement has become the most compelling point in both theoretical study and experimental measurement.In this paper, some fundamental theories in quantum information, quantum entanglement and quantum teleportation, are introduced first, then the interaction between atoms and field. Jaynes-Cummings model is the most important and most fundamental theoretical model of the interaction between radiations and mass, it describes the interaction between a 2-energy-level atom and single mode field. The normal and extended Jaynes-Cummings model of interaction between atoms and field are introduced in this paper, and also the models with atomic moving and multi-photon. At last, based on the thermal entanglement phenomenon of Heisenberg quantum model, thermal entanglement was extended to QED system, and the thermal entanglement phenomenon of atomic moving and multi-photon J-C model is studied by concurrence entanglement. The results imply that:1. There is a critical temperature in the system. No entanglement between atoms and field will occurrence when the environment temperature is higher than this critical one.2. Thermal entanglement will raise follow the increase of coupling coefficient and photons produced during the atomic transition.3. There will be no entanglement between atoms and field if atoms are slack.4. Thermal entanglement is function of atomic moving speed, photon number, and environment temperature. It will follow their changing.For the environment temperature is very important to system entanglement, it can be used as the processing unit of quantum information, based on the environment temperature and coupling coefficient between atoms and field, by selecting proper QED system.