Nuclear Magnetic Resonance Implementation Of Quantum Algorithms & Information Processing

Quantum information processing (QIP) is the use of inherently quantum physics to represent and manipulate information, which has capabilities that exceed those of traditional"classical"information techniques. Thus the resultantly powerful abilities have intrigued enormous interest in this field of research. As the coherent manipulation and control of the fragile quantum system in the actual experiments, practically building quantum computers has proved extremely difficult. However, of the extant methods, liquid-state Nuclear Magnetic Resonance (NMR) is arguably the most successful one. Now, the achievements on liquid-state NMR QIP, especially the rich source of basic quantum control techniques accumulated for QIP, will contribute to the next generation of quantum information processors and the understanding of the power of quantum information processing. Therefore, the experimental and theoretical investigation of liquid-state NMR QIP is chosen as the subject of my dissertation, which involves the study of the quantum property, NMR quantum computation and quantum communication. Significant new results are shown as follows:A concrete scheme of preparing a pseudo-pure state (PPS) by the operation of several simultaneous line-selective pulses has been proposed and experimentally implemented with NMR in two-qubit system. It has the simpler operation and the less errors than the previous methods.Two interferometric complementarities—between path distinguishability and the visibility of single-particle interference fringes and between the visibilities of one- and two-particle interference fringes—have been experimentally testified in NMR macroscopical ensemble, which is the experimental demonstration of quantum properties of NMR ensemble system. Meanwhile, the experimental results also provide the quantum mechanical foundation. Besides, equality V_i² + V₁₂² + P_i²= 1 is obtained, which implies many important aspects.A quantum circuit is introduced to describe the preparation of a labeled PPS and has been experimentally implemented with NMR. Meanwhile, a 3-qubit Bernstein- Vazirani algorithm has been experimentally demonstrated on a 4-qubit quantum information...