Realization Of Quantum State Measurement And Quantum State Discrimination With Nuclear Magnetic Resonance

Quantum information is a new subject from the combination of quantum mechan-ics and information science. Compared with classical computers, quantum computersmanifest distinct advantages in many respects, for example, to cope with some certainproblems which are NP problems for classical computers and to simulate the evolu-tion of quantum system. The resultantly powerful abilities have intrigued enormousinterest in this field of research and become the various governments, science societiesand information industrial circles. Of the extant methods, the processing technique ofliquid-state Nuclear Magnetic Resonance (NMR) is the most mature one, it has fruitfulresults. To this day the largest experiment of quantum bit, the coherent control of 12qubits has been implemented on NMR.In this thesis, we discuss and realize some important problems on Quantum Infor-mation Processing Research with NMR, which are about quantum measurement.The first two chapter are introductions of base conception and NMR technique.The first chapter is the introduction of Quantum Information, including the carrier ofquantum information - quantum bit,realization of the basic unit of information - quan-tum gate and a variety of physical realization systems. The second chapter is abouthow we process the corresponding quantum control in NMR system , including themost basic preparation of pure states, the basic unit of the gate, the method of quantumstate measurement and the realization in experiment.We realized the experiment about Symmetric Informationally Complete-POVMmeasurement, chapter III and chapter IV are related. Chapter III introduce the the-ory of quantum generalized measurement, the the measurement model, and the mostcommonly used generalized measurement - POVM measurement. Chapter IV of thefollowing is our experiment on the Symmetric Informationally Complete-POVM mea-surement. There is also some introductions of Symmetric Informationally Complete-POVM measurement scheme.We realized the experiment about unambiguous quantum states discrimination with a programmable device, chapter V is related. Quantum states discrimination andquantum measurement are of a cross-cutting research in the same field. By compari-son, the quantum states discrimination is more suitable for dealing with more compli-cated situations, and better for select in some not completely information cases. Thebeginning of this chapter brie?y introduced the main facing tasks of quantum statesdiscrimination and two different types of strategies: unambiguous discrimination andminimum error discrimination. After this is the proposal of unambiguous discrimina-tion in the realization of a programmable device functions and advantages. Then, wediscuss the feasibility of this device and realize the experiments about it; Finally, thereis some improvement about this program.Chapter VI describes leading the dephasing into a typical 4-qubit state of the clus-ter state. We use it to discuss the robust of Cluster state to against decoherence. Weintroduce the form of cluster state, dephasing mechanisms and experimental simulationapproach.