Using Josephson Charge Qubits System To Realize The Transfer Of Quantum State

In the20th century, the rapid development of classical information technology enhanced the tremendous progress in our human society. However, in today’s development, the modern civilization needs higher-level technology of information. So, quantum information science appear to meet this requirement. Quantum information is the combination of quantum theory and information science, the key of quantum information is the quantum state and its maneuverability. Quantum state is defined by different independent energy levels and it is the basic unit of quantum information processing. A two-level quantum system will be called a qubit. At present, solid-state superconducting quantum system is focused on by many researchers, and it opens a new field for future information science and it also has great potentiality in realizing a quantum computer. Superconducting Josephson quantum system has become one of the choices to realize large-scale quantum computation because it has special coherence and scalability. In this paper I concentrated on how to make quantum state by searching for a kind of superconducting Josephson circuit system, and study its manipulation.Basing on understanding the previous achievement of others, I constructed a type of Josephson charge qubit circuit system to represent four qubits information by using the nonlinear effect of Josephson junction. Using the constructed system, quantum state|1000> can evolve as|1000>, i.e. the information can exchange between the first qubit and the fourth qubit. By modulating the external magnetic flux, the ideal transfer of an excited state|1> from the first qubit to the fourth qubit can be realized in both the homogeneous and inhomogeneous transmission channels. Moreover, the average fidelity of state transfer is also analyzed.