Theoretical Study Of Quantum Communication Process In Linear Optical System

Quantum communication is an important research of quantum information, which provides a new approach for the secure transmission of information, and the subject has been gradually shifting from theory to experiment in recent years. This paper will mainly discuss how to realize the single-qubit gate operation in molecules and the quantum communication in linear optical system.Firstly, a new experimental protocol of teleportation is proposed to realize quantum teleportation by using hyperentangled photon pairs, and by this protocol the probability approaches unity. This set-up is made of hyper-entangled photon source, linear optical elements and conventional photon detectors.Secondly, utilized polarization entangled photons, a linear optical protocol for generating random quantum key distribution (QKD) is proposed for quantum key distribution, which is made up of EPR-source, linear optical elements, and conventional photon detectors. It is shown that total efficiency of QKDη=100% in theory.Finally, we propose a scenario to realize single-qubit gate utilizing heteronuclear diatomic rovibrational states as qubits. Numerical calculations show that single qubit gate operation in the electronic ground state of LiH molecule can be obtained.