This article treats about the status on the new scientific problems of physics and electronics in the 21st century,involving vacuum energy,negative mass of electron,quantum potential,virtual particles,superstring theory and tachyons;as well as the EPR thinking experiment,quantum entanglement ,quantum teleportation,quantum information theory and quantum computers.

Which was based on teleportation and quantum entanglement swapping in quantum optics.

The quantum entanglement of the two-photon Tavis-Cummings model;

New theory of quantum entanglement;

Quantum Entanglement and Decoherence;

The Formula of Entanglement Evaluation for Two-Electron Systems;

By using the concept of negativity, we investigate entanglement of (1/2,1) mixed-spin anisotropic XY model and obtain the numerical results of entanglement of two spins in a transverse field at finite temperature.

In addition to being of fundamental interest in quantum mechanics, entanglement as quantum correlations among quantum systems is a key element in rapid developing quantum informatics.

The fundamental principles and the main experimental advances of quantum teleportation about two_photon entangled states were reviewed.

Based on the necessity and importance of the quantum information theory, this paper chooses three aspects of quantum communication to study: Von Neumann entropy of quantum entangled state, controlled exchange of quantum entangled state, controlled quantum dense coding.

First, we introduce EPR entangled state in Fock space.

Universal telecloning of quantum entangled states;

This paper describes what is quantum bit and what is quantum entangled state, and how to realize Bell state by using quantum circuit, proposes a quantum circuit of simple structure to realize quantum teleportation based on Bell State.