The Realization Of Quantum Teleportation Under The Control Of A Third Party

Since1993Bennett et al proposed a scheme for teleporting an unknown single-particle quantum state, for how to transfer quantum states has been conducted in-depththeoretical and experimental studies has got a lot of fruitful progress in theory andexperiment. This thesis describes the basic concepts and properties related to quantumteleportation of quantum mechanics in detail, and makes a review of traditional schemesfor single qubit and multi-qubit teleportation using Bell states as quantum channel. On thisbasis, as the preparation of Bell states faces great difficulties in experiment, we proposetwo new programs for teleportation in driven field and under the control of a third partyrespectively, the new programs can reproduce the maximum probability of the initialunknown state without the Bell-based measurements of the particles. Finally, we make asummary of the recent progress in quantum teleportation, and give an outlook of thefantastic topic.In the program for teleportation in driven field, we choose a two-particle non-maximally entangled state as the quantum channel without considering the impact of cavitydissipation and external environment. We get the evolution equation of the atoms in thecavity field by controlling time and adjusting the frequency of external field. At last, weintroduce an auxiliary particle to reproduce the maximum probability of the initialunknown state by measuring the single particle, the probability of success is equal to twicethe square of partially entangled smaller superposition coefficients matrix.In the program for teleportation under the control of a third party, we choose a set oftwo-qubit maximally entangled states and three-qubit partially entangled states as a sharedquantum channel, the three-qubit partially entangled states where as the channel can be physically realized from the generalized Greenberger-Horne-Zeilinger (GHZ) states byperforming a H (Hadamard) gate and a CNOT gate on it, more importantly, compared tothe channels of the general three-particle states, our states allow the transfer of a maximumnumber of bits from the sender to the receiver. The sender Alice measures his qubits in theBell basis, then tells the measurement results to controller Charlie from the a classicalchannel, now Charlie measures his qubits in the partially entangled Bell basis, and tellsBob of the results, at last in order to recover the teleported states successfully, Bob needs toperform a corresponding unitary transformation. In addition, this program uses anon-maximally entangled states as a shared channel by introducing controller Charlieinstead of an auxiliary particle, under the control of Charlie, the probability of thesuccessful quantum teleportation may reach100%.