Theoretical Study Of Quantum Teleportation And Super-coding

Quantum information can be interpreted as a generalization for all manners of operations that might be related to information processing using quantum mechanics. It encompasses subjects such as quantum computation, quantum teleportation, the no-cloning theorem and so on. Quantum teleportation is important to help people know the secret laws of nature in physical field. If the technology of quantum teleportation is extensively realized, it will be applied in quantum computation and quantum communication. Since Bennett et al. presented the first quantum teleportation protocol in 1993, lots of quantum teleportation schemes have been presented by many groups. In this paper, two general quantum teleportation schemes via two different non-maximally entangled states are proposed, and including a supercoding scheme is also investigated using a partial symmetric quantum channel.Scheme 1: We propose a scheme for controlled teleportation of a unknown two-particle state using a four-particle GHZ state as a quantum channel, and one of these particles works as the controlling particle. The sender and the controller perform a series of measurements and operations on their own particles respectively and send their results to the receiver. According to the measurement results, the receiver will get the state sent by sender by doing proper unitary transformations.Scheme 2: A controlled quantum teleportation scheme of an N-particle unknown state is proposed when N groups of three-particle GHZ-like states are utilized as quantum channels. For an arbitrary N-particle unknown state, the sender performs Bell-state measurements on her qubits, and the controller takes Hadamard gate operations and then performs computational basis measurements on his qubits, then the receiver can reconstruct the N-particle unknown state by introducing auxiliary particles and making appropriate unitary transformations and finally performing computational basis measurements on the auxiliary particles if he cooperates with the controller. The quantum information of N-particle unknown state is transmitted from the sender to the receiver under the control of controller.Scheme 3, We investigate a three-party dense coding scheme in the case of partial-symmetric quantum channels. we show that for the same quantum channels , the amount of the classical information transmitted from two senders to one receiver is different by using different ways of quantum operations.