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.

No description available.

Ge Guo Qin. / "April 18, 2001." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 129-143). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

This thesis examines the statistics and dynamics of turbulent flow structures generated by towing a grid through a tank of water. The structures were made visible by recording the paths of aluminum tracers moving with the water surface. Flow patterns recorded using a time-exposure method were manually analyzed to extract information on the structure statistics. This two-dimensional flow field was found to be composed of closed rotating 'surface eddies', open and largely translational 'river' motion and stagnant regions. Energy distributions of the eddies and rivers were obtained and characterized by Boltzmann type distributions. A newly developed computer-automated structure identification and flow field analysis system was used to study the structure dynamics. The system analyzes digital images obtained from video recordings of the tracer motion. The predominant evolution processes of initial vortex production, eddy pairing, viscous decay and the omega decay were examined. Flow Reynolds numbers, based on bar spacing, of about 10,000 were examined. The structure statistics and dynamics study was performed in order to examine the validity and viability of a new model for turbulence. The model predicts the evolution of a population of structures using rate equations where the rate coefficients are determined by the individual structure dynamics. A summary of the model is presented and contrasted with models based the the Reynolds stresses as well as computational models. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Yes / A quantum system with variables in Z(d) is considered. Coherent density matrices and coherent projectors of rank n are introduced, and their properties (e.g., the resolution of the identity) are discussed. Cooperative game theory and in particular the Shapley methodology, is used to renormalize coherent states, into a particular type of coherent density matrices (dressed coherent states). The Q-function of a Hermitian operator, is then renormalized into a physical analogue of the Shapley values. Both the Q-function and the Shapley values, are used to study the relocation of a Hamiltonian in phase space as the coupling constant varies, and its effect on the ground state of the system. The formalism is also generalized for any total set of states, for which we have no resolution of the identity. The dressing formalism leads to density matrices that resolve the identity, and makes them practically useful.

Yes

Orientador: Gastão Inácio Krein / Banca: Maria Teresa Climaco dos Santos Thomaz / Banca: Gabriel Santos Menezes / Resumo: A presente dissertação tem como objetivo principal fazer uma revisão sobre o uso de estados coerentes para calcular a função de partição gran canônica de sistemas fermiônicos, sem empregar integrais de trajetória. Após discutir um método de cálculo baseado numa expansão de altas temperaturas, formulamos uma teoria de perturbação otimizada empregando campos auxiliares via transformação de Hubbard-Stratonovich. Aproximações não perturbativas tradicionais de campo médio tipo Hartree-Fock e de BCS são obtidas em ordem zero da teoria de perturbação otimizada. Correções não perturbativas à aproximação de ordem zero são implementadas usando uma expansão em potências de uma interação modificada, em que os efeitos dos campos médios são subtraídos da interação original do Hamiltoniano da teoria / Abstract: The primary aim of the dissertation is to review the use of coherent states for the calculation of the grand canonical partition function for fermion Systems, without employing path integrals. After discussing a calculational method based on a high temperature expansion, we formulate an optimized perturbation theory employing external fields via the Hubbard-Stratonovich transformation. Traditional non-perturbative mean field approximations like Hartree-Fock and BCS are obtained in zeroth order in the optimized perturbation theory. Non-perturbative corrections to the zeroth order approximation are implemented through a power series expansion of a modified interaction, where the effects of the mean fields are subtracted from the original interaction of the Hamiltonian of the theory / Mestre

As quantum systems can never be isolated from their environment entirely, it is expected that the spacetime fluctuations will influence their evolution. In particular, the environmental interaction may cause the loss of quantum superpositions, or decoherence. In this thesis, we examine the effects of the quantised environmental background on a range of bosonic fields in the formalism of open quantum systems. We first quantise linearised gravity in a gauge invariant way, using Dirac's constraint quantisation. We then use the influence functional technique to obtain an exact master equation for general bosonic matter interacting with weak gravity. As an application of this, we investigate the decoherence of free scalar, electromagnetic and gravitational fields. For long-time decoherence, under the Markov approximation, the dissipative terms in the master equation vanish, leading to no decay of quantum interferences. As a short-time effect, we study the master equation for a many particle state of a free scalar field, massive or massless and relativistic or non-relativistic. We find that in this case, the particles exhibit a counterintuitive behaviour of bundling towards the same quantum state that is not shared by the single particle master equation. Such collective effects, as well as possible long-time decoherence for fields in an external potential may have important implications in setting limits for precision measurements and astronomical observations.