Entanglement Protection Based On Weak Measurement And Its Applications In Quantum Signature

Quantum entanglement,as an indispensable physical resource,plays an important role in quantum communication.However,due to the influence of external noise environment,quantum decoherence often occurs and leads to the destruction of the integrity of the quantum information in practical applications.Thus it is a hot topic to resist the influence of noise environment on quantum entanglement in the research of quantum information theory.We mainly explore the protective effect of weak measurement and environmentassisted measurement on entangled state in this paper.And we have obtained the following three conclusions: the fidelity preserving scheme of -type entangled state based on weak measurement and weak measurement reversal is presented;by employing the environment-assisted measurement and weak measurement,we give our entanglement preserving scheme of the four-particle cluster state;a novel quantum broadcasting multiparty blind signature scheme with four-particle cluster states is proposed.