Optimize The Continuous Variable Quantum Teleportation Fidelity

A combination of quantum mechanics and information science yields a new subject, namely, quantum information science. It pioneers a new canto of quantum mechanics appliance. Quantum entanglement is a strange phenomena existing many complex subsystems, that is, the measure results of a subsystem can not independent the measure parameters of else subsystems. Lately, with the vigorous development of quantum information, quantum entanglement states has been widely applied in each field of quantum information. In 1993, Bennett et al first advance the scheme of discrete variables quantum teleportation. In 1994,Vaidman first advance the concept of continuous variables quantum teleportation in theory. Henceforth, quantum teleportation acquire striking development in theory and in experiment. Currently, quantum teleportation is one of the most striking interesting field in quantum communication. Fidelity is an important quality in the subject of quantum information. It can measure the performance of quantum teleportation and describe the similarity between the input state and the teleported state. In order to obtain better output results, scientists have tried to increase the fidelity of quantum teleportation with many methods and acquire many productions. In this thesis, we focus our research on a series of problems of the fidelity of continuous variables quantum teleportation applying bright two-mode squeezed state for entangled source. The main results of this thesis are as follows:1. Optimizing the fidelity of coherent state of quantum teleportation. By the former conclusion of employing two-mode squeezed vacuum state for entangled channel adjusting the output field displacement gain to optimize the fidelity of quantum teleportation, we study that by choosing properly the displacement parameters of bright two-mode squeezed state can further improve the fidelity of quantum teleportation employing bright two-mode squeezed state for entangledchannel and note that this method is more suitable for the case of small squeezing degree of the initial two-mode squeezed state. Specially, under nonzero squeezing conditions, by choosing properly the output field displacement gain and the displacement parameters of bright two-mode squeezed state, we can fulfill that fidelity is 1 that is not anamorphic quantum teleportation in theory. It breakthrough the restrain of because squeezing can not infinite so fidelity always less than 1 employing two-mode squeezed vacuum state for entangled channel.2. Optimizing the fidelity of Schrodinger cat states of quantum teleportation. By the former conclusion of employing two-mode squeezed vacuum state for entangled channel adjusting output field displacement gain to optimize the fidelity of Schrodinger cat states of quantum teleportation, we find that by choosing properly the displacement parameters of bright two-mode squeezed state can further improve the fidelity of quantum teleportation. This method is more suitable similarly for the case of small squeezing degree of the initial two-mode squeezed state.3. We study the fidelity of single mode squeezed state employing two-mode squeezed vacuum state and bright two-mode squeezed statefor entangled channel respectively. We validate employing two-mode squeezed vacuum state for entangled channel adjusting the output field displacement gain also can optimize the fidelity of single mode squeezed state of quantum teleportation. We fetch the fidelity of single mode squeezed state of quantum teleportation employing bright two-mode squeezed state for entangled channel and analyze the effect of squeezing parameters of single mode squeezed state toward the fidelity.