In the field of optical fiber communication, the IM/DD system had been used to commercial usage for many years. The merits of this scheme are its simple idea and easiness to realize. However, such a system can not afford the requirement of the capacity people demand anymore. Recently, the research of the optical fiber communication is focused on how to increase the spectral efficiency to attend the high speed transmission. Coherent system had been investigated widespreadly a few tens years ago. This technique could improve the spectral efficiency. Nevertheless, the difficulty of coherent system was its receiver circuit was quite complicated and could not be realized at that time. Accompanying with the improvement of the technique, a developed technique called digital signal processing (DSP) could overcome such difficulties. This master thesis is focused on how to cooperate these two techniques that may be required for the next generation high speed transmission system.

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Wong Sik Lik = 廣義薛定諤貓態之非經典性質 / 王適力. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 120-124). / Text in English; abstracts in English and Chinese. / Wong Sik Lik = Guang yi xue ding e mao tai zhi fei jing dian xing zhi / Wang Shili. / Acknowledgements --- p.i / Abstract --- p.ii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Coherent States and Schrodinger Cats --- p.4 / Chapter 2.1 --- Short review on Quantization of single- mode electromagnetic field --- p.5 / Chapter 2.2 --- Number states as field states --- p.6 / Chapter 2.3 --- Coherent states as field states --- p.7 / Chapter 2.4 --- Features of Coherent states --- p.8 / Chapter 2.4.1 --- Coherent states and Minimum Uncertainty --- p.8 / Chapter 2.4.2 --- Coherent states and Poissonian distribution --- p.10 / Chapter 2.5 --- Non- Classical properties of Schrodinger Cat States --- p.12 / Chapter 2.5.1 --- Quadrature Squeezing of ECS --- p.13 / Chapter 2.5.2 --- Photon Statistics of ECS --- p.14 / Chapter 2.5.3 --- Wigner function of ECS --- p.15 / Chapter 2.5.4 --- Q-function of ECS --- p.23 / Chapter 3 --- Generalized Schodinger Cat States : Perelomov's type GSCS & Barut-Girardello's type GSCS --- p.26 / Chapter 3.1 --- Review on SU(1，1) Lie algebra --- p.26 / Chapter 3.2 --- "SU(1,1) Perelomov's type GCS" --- p.28 / Chapter 3.3 --- "SU(1,1) Perelomov's type GSCS" --- p.30 / Chapter 3.4 --- "SU(1,1) Barut-Girardello's type GCS" --- p.32 / Chapter 3.5 --- "SU(1,1) Barut-Girardello's type GSCS" --- p.33 / Chapter 4 --- Nonclassical properties of Perelomov's type GSCS --- p.36 / Chapter 4.1 --- Nonclassical properties of PGSCS of the single-mode realization --- p.36 / Chapter 4.1.1 --- Quadrature Squeezing of PGSCS --- p.36 / Chapter 4.1.2 --- Photon Statistics of PGSCS --- p.41 / Chapter 4.1.3 --- Q-function of PGSCS --- p.43 / Chapter 4.1.4 --- Wigner function of PGSCS --- p.49 / Chapter 4.2 --- Nonclassical properties of PGSCS of the two-mode realization --- p.49 / Chapter 4.2.1 --- Quadrature Squeezing of PGSCS --- p.49 / Chapter 4.2.2 --- Photon Statistics of PGSCS --- p.52 / Chapter 4.2.3 --- Q´ؤfunction for PGSCS --- p.55 / Chapter 4.2.4 --- Wigner function of PGSCS --- p.58 / Chapter 4.3 --- Nonclassical properties of PGSCS of the Holstein-Primakoff realization --- p.60 / Chapter 4.3.1 --- Quadrature squeezing of PGSCS --- p.60 / Chapter 4.3.2 --- Photon Statistics of PGSCS --- p.62 / Chapter 4.3.3 --- Q-function of PGSCS --- p.62 / Chapter 4.3.4 --- Wigner function of PGSCS --- p.69 / Chapter 5 --- Nonclassical properties of Barut-Girardello's type GSCS --- p.71 / Chapter 5.1 --- Nonclassical properties of BGSCS of the two- mode bosonic realization --- p.71 / Chapter 5.1.1 --- Squeezing properties of BGSCS --- p.71 / Chapter 5.1.2 --- Photon Statistics of BGSCS --- p.74 / Chapter 5.1.3 --- Q- function of BGSCS --- p.77 / Chapter 5.1.4 --- Wigner function of BGSCS --- p.77 / Chapter 5.2 --- Nonclassical properties of BGSCS of the Holstein-Primakoff realization --- p.81 / Chapter 5.2.1 --- Squeezing properties of BGSCS --- p.81 / Chapter 5.2.2 --- Photon statistics of BGSCS --- p.83 / Chapter 5.2.3 --- Q- function of BGSCS --- p.83 / Chapter 5.2.4 --- Wigner function of BGSCS --- p.85 / Chapter 6 --- "SU(1,1) Squeezing and Generalized Q´ؤfunction" --- p.90 / Chapter 6.1 --- "SU(1,1) Squeezing of PGSCS & BGSCS" --- p.90 / Chapter 6.1.1 --- "Reviews on SU(1,1) squeezing" --- p.90 / Chapter 6.1.2 --- "SU(1,1) Squeezing of PGSCS" --- p.92 / Chapter 6.1.3 --- "SU(1,1) Squeezing of BGSCS" --- p.93 / Chapter 6.2 --- "SU(1,1) Generalized Q´ؤfunction" --- p.95 / Chapter 6.2.1 --- GQk- function of PGSCS --- p.97 / Chapter 6.2.2 --- GQk-function of BGSCS --- p.101 / Chapter 6.2.3 --- GQk´ؤfunction of Glauber coherent state and Squeezed vacuum --- p.103 / Chapter 7 --- Discussion and Conclusion --- p.109 / Appendices --- p.111 / Chapter A --- Derivation of Equations 4.1 and 4.2 --- p.112 / Chapter B --- Derivation of Equation 4.16 --- p.115 / Chapter C --- Derivation of < n > and < n2 > on P.75 --- p.117 / Chapter D --- Deriavation of Equation 6.10 --- p.119 / Bibliography --- p.120

Ho, Sai Wah = 鑽石氮-空缺中心自旋的退相干研究及控制 / 何世華. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 62-68). / Abstracts in English and Chinese. / Ho, Sai Wah = Zuan shi dan-kong que zhong xin zi xuan de tui xiang gan yan jiu ji kong zhi / He Shihua. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- NV center in diamond --- p.6 / Chapter 2.1 --- Why NV centers? --- p.6 / Chapter 2.2 --- NV center --- p.8 / Chapter 2.3 --- Hamiltonian of the spin system --- p.11 / Chapter 3 --- Decoherence calculation - Cluster-correlation expansion --- p.13 / Chapter 3.1 --- The decoherence problem --- p.13 / Chapter 3.2 --- Quantum many-body theory: History and method --- p.17 / Chapter 3.3 --- General theory of cluster-correlation expansion --- p.19 / Chapter 3.4 --- Different physical processes and the pictorial understanding: Spin pathways in Bloch sphere --- p.21 / Chapter 3.4.1 --- Dynamical fluctuation versus inhomogeneous broadening --- p.21 / Chapter 3.4.2 --- Single nuclear spin dynamics --- p.22 / Chapter 3.4.3 --- Nuclear spin pair dynamics --- p.24 / Chapter 3.4.4 --- Higher order spin cluster dynamics --- p.27 / Chapter 4 --- Dynamical decoupling theories and experiments --- p.28 / Chapter 4.1 --- Dynamical decoupling: History --- p.28 / Chapter 4.2 --- Pulse sequences --- p.29 / Chapter 4.2.1 --- Spin echo (SE) --- p.30 / Chapter 4.2.2 --- Carr-Purcell-Meiboom-Gill (CPMG) sequence --- p.31 / Chapter 4.2.3 --- Concatenated dynamical decoupling (CDD) --- p.31 / Chapter 4.2.4 --- Uhrig dynamical decoupling (UDD) --- p.32 / Chapter 5 --- Dynamics of the spin clusters --- p.34 / Chapter 5.1 --- Convergence of CCE under external magnetic field and pulse sequence --- p.34 / Chapter 5.2 --- Zero magnetic field regime: single spin and spin pair induced dynamics --- p.35 / Chapter 5.2.1 --- Free induction decay --- p.36 / Chapter 5.2.2 --- Dynamical decoupling control: UDD1-5 --- p.37 / Chapter 5.3 --- Small magnetic field regime: Single spin and spin pair induced dynamics --- p.38 / Chapter 5.3.1 --- Single spin induced dynamics: single spin induced re- vivals under dynamical decoupling sequences --- p.38 / Chapter 5.3.2 --- Single spin induced dynamics: Periodicity of revivals un- der different dynamical decoupling sequences --- p.42 / Chapter 5.3.3 --- Single spin induced dynamics: Short time modulation and envelope under the effect of Fermi contact and dy- namical decoupling sequences --- p.45 / Chapter 5.3.4 --- "Single spin and spin pair induced dynamics: Revival, os- cillation and decay under dynamical decoupling sequences" --- p.48 / Chapter 5.4 --- Large magnetic field regime: Single spin and spin pair induced dynamics --- p.50 / Chapter 5.4.1 --- Free induction decay --- p.50 / Chapter 5.4.2 --- Dynamical decoupling control: UDD 1-5 --- p.52 / Chapter 6 --- Application: Atomic scale magnetometry --- p.55 / Chapter 7 --- Conclusion --- p.59 / Bibliography --- p.62 / Chapter A --- Derivation of modulation and envelope frequency using second order perturbation theory --- p.69

In this thesis we investigate what modern nonlinear-dynamical methods can tell us about some longstanding problems in atomic physics. It is well-known that it is very difficult to prevent electronic wavepackets from spreading, and that is where we bring in coherent states. We evaluate two strategies for forming coherent states in atomic physics problems with large Coriolis interactions : One involves the use of the "Cranked Oscillator" model to construct nondispersive wavepackets. We show that it is possible to keep the wavepackets from spreading while manipulating them with dipole fields with arbitrary time profiles. The second strategy involves using additional external fields to create a stable outer minimum far from the core. Whenever this minimum approximates a harmonic well it has its own subset of near-harmonic eigenstates and nearly-coherent states can be constructed. As examples of this strategy we study two-particle ion pair systems in a applied homogeneous magnetic field, and a weakly bound heavy-ion pair (Hydrogen positive and negative ions), where the nonspreading wavepacket corresponds to the motion of the drifting electron-ion or heavy ion pair in relative coordinates. We look for a Horseshoe Construction in the dynamics of the ionization of a highly excited two-electron atom by an classical-mechanical investigation.

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This thesis describes the design and performance of a 94 GHz short pulse, low duty cycle, high resolution coherent injection locked radar system for sensor applications, with the specific use as an early warning radar ,against high voltage transmission lines. The recent development of solid-state components for frequencies around 94 GHz has made it possible to design coherent millimetre-wave radar systems. Key components of such systems are high power pulsed silicon Impact oscillators, CW Impact oscillators, second harmonic Gunn oscillators, filters, circulators, isolators, couplers, and antennas. Elementary system specifications are derived for the delivery vehicle and the millimetre-wave sensor. Each of the separate components of the system were designed, built, and tested. Measurements were taken with the sensor and are presented. Specific attention is given to the measurement of intra-pulse phase ripple, additive noise, injection locking and coherency. The above-mentioned parameters are critical in the design of a coherent sensor and special care should be given to the various components in the design stage. The sensor is not built into a carrier system yet but was built up as a laboratory model and measurements were taken from the laboratory to various objects and distances outside the laboratory. There is only one article in literature [1] which described a 66 GHz collision warning sensor for helicopters. The system is a noncoherent pulsed radar with the following specifications:

Because of the Human Genome Project, enormous quantities of biological data, e.g., microarray data, are generated. Since the amount of biological data is very large, data mining techniques can be used to help biologists efficiently analyze the biological data. For microarray data, biclustering, which performs simulataneous clustering of rows (e.g., genes) and columns (e.g., conditions), has proved of great value for finding interesting patterns. There were several types of biclusters proposed. To mine biclusters with coherent values, most of the previous methods need to compute Maximum Dimension Sets (MDSs) for every two genes in the microarray data. Since the number of genes is far larger than the number of conditions, this step is inefficient. On the other hand, to mine biclusters with coherent evolutions, the Co-gclustering method was proposed which could simultaneously find biclusters with both coregulated and negative-coregulated patterns. However, its time complexity is exponential to the number of conditions, which is not efficient. Therefore, in this dissertation, to efficiently solve the problem of biclustering for microarray databases, first, we propose a Condition Enumeration Tree (CE-Tree) method which mines biclusters with coherent values. Second, we propose an Up-Down Bit Pattern (UDB) method which mines biclusters with coherent evolutions. In the first proposed method, CE-Tree, to mine biclusters, instead of generating MDSs for every two genes, we generate only MDSs for every two conditions. Then, we expand the CE-Tree in a special local breadth-first within global depth-first manner to efficiently find the clustering result. From the experimental results on real data, we have shown that the CE-Tree method could mine biclusters more efficiently than several previous methods. In the second proposed method, UDB, we utilize up-down bit patterns to record the condition pairs where one gene is upregulated or downregulated. Then, we utilize bit operations and apply a heuristic idea on these up-down bit patterns to efficiently find the clustering result. As compared to the Co-gclustering method, the UDB method reduces the time complexity from exponential time to polynomial time. From the experimental results on real data, we have shown that the UDB method is more efficient than the Co-gclustering method.

One of the goals of perception is to learn to respond to coherence across space, time and modality. Here we present an abstract framework for the local online unsupervised learning of this coherent information using multi-stream neural networks. The processing units distinguish between feedforward inputs projected from the environment and the lateral, contextual inputs projected from the processing units of other streams. The contextual inputs are used to guide learning towards coherent cross-stream structure. The goal of all the learning algorithms described is to maximize the predictability between each unit output and its context. Many local cost functions may be applied: e.g. mutual information, relative entropy, squared error and covariance. Theoretical and simulation results indicate that, of these, the covariance rule (1) is the only rule that specifically links and learns only those streams with coherent information, (2) can be robustly approximated by a Hebbian rule, (3) is stable with input noise, no pairwise input correlations, and in the discovery of locally less informative components that are coherent globally. In accordance with the parallel nature of the biological substrate, we also show that all the rules scale up with the number of streams.