Study On Quantum Entanglement Properties Of Atom State In System Of Atom Interacting With Light-Field

Quantum informatics as a newly emerging subject didn't rise in the world until 1994.Though the time is short, a series of important breakthroughs have been gained. Quantuminformatics mainly includes quantum information, quantum communication, quantum opticalcommunication, quantum computation and so on. And quantum entanglement is one of themost significant development direction in the field of the quantum informatics.In this thesis, we firstly systematically introduce the development of quantuminformatics in recent years both in china and abroad, basic concept and basic theory ofquantum entanglement and quantum entropy. It is involved quantum entangled state, quantumteleportation, quantum non locality, quantum information entropy and so on. Then wesummarize some methods in quantum entanglement measurement and purification ofquantum entangled states. Base on these theories and the complete quantum theory, we studythe properties of quantum entanglement of atom state in the system of theΛtype three levelatom interacting with single mode light field and get some new meaningfull results. Theresults show that we can find the properties of the quantum entanglement in the system of alllight filed states from coherent state to fock state interacting withΛthree level atom basedon the properties of the binomial state light field. Also, photon probability distributioncoefficient, detuning, coupling constant between atoms and atom field nearly all can affectthe entanglement properties of the system. With the increase of the photon probabilitydistribution coefficient from 0 to 1, the entanglement properties of the system decrease fastly;and the ratio of detuning to coupling constant can affect the most entanglement and theevolution periodicity of the system, with the increase of the ratio, the periodicity ofentanglement increase fastly, and the most entanglement of the system increase slowly, Andvice versa.