UQ Theses (RHD) - UQ staff and students only - UQ eSpace
http://espace.library.uq.edu.au/
The University of QueenslandenFez http://blogs.law.harvard.edu/tech/rssQuantifying the Influence of Liner Wear on SAG Mill Performance
http://espace.library.uq.edu.au/view/UQ:331580
2014-06-01T17:47:22Z
Toor, Paul Quantitation of chemosensitivity in acute myeloid leukemia
http://espace.library.uq.edu.au/view/UQ:366016
2015-07-29T15:39:19Z
Lihou, Michelle G Quantitation of chromium (V) in environmental systems
http://espace.library.uq.edu.au/view/UQ:365840
2015-07-29T15:14:42Z
Chappell, John Quantitative Analysis of Mobilisation and Functional Status among Older Patients in Hospital Settings
http://espace.library.uq.edu.au/view/UQ:263287
Prolonged bed rest and immobilisation are major factors contributing to functional decline among older patients in hospital. As patient activity is rarely documented quantitatively in day-to-day clinical practice, there is no clear guideline of how much physical activity is sufficient to maintain or improve the functional capacity of older patients. The use of accelerometry in activity monitoring may provide an objective and efficient method to measure the amount of daily activity accurately. This information can be used to promote and manage activity in rehabilitation settings. There has been limited validation work in the area of accelerometry monitoring conducted with a large sample of older mobility impaired patients in the hospital settings. A literature review was conducted to identify all studies that validated the use of raw acceleration signals from accelerometer devices together with an activity classification algorithm, to classify human postural movements and mobility into categories of lying, sitting, standing, walking, sit-to-stand and stand-to-sit transitions. Fifty-four studies were identified, and most of these studies involved attaching triaxial accelerometer devices onto the waist of their subjects. The subjects in these studies were healthy individuals (n=37) and patients (n=17). Of the 17 studies with patients, only six of them included older patients in hospital with rehabilitation needs. This review highlighted that activity monitoring with multiple accelerometer devices was shown to be accurate on healthy individuals. However, limited validation work was conducted on older mobility impaired patients with a single waist-mounted triaxial accelerometer device. The aims of this research project were to validate the activity classification algorithm using acceleration signals to classify the physical activities of older patients, and to determine whether the accelerometer devices can be applied in the geriatric rehabilitation settings as activity monitors for everyday clinical use. A framework for a series of studies was adopted to assess the efficacy of transforming the accelerometry activity monitoring method through to application in everyday clinical practice. There are six levels in this framework: technical efficacy, diagnostic accuracy efficacy, diagnostic thinking efficacy, therapeutic efficacy, patient outcome efficacy, and societal efficacy. The context of this thesis covered the first four levels of the framework and future work would be required for the last two levels. This research project consisted of four individual clinical trials outlined as follows. Clinical Trial 1 covered the technical efficacy level. The aims of this trial were to evaluate the quality of the acceleration data collected from biaxial and triaxial accelerometer devices, and to evaluate the performance of a rule-based and a wavelet-based activity classification algorithms. This trial was conducted with five healthy individuals. The triaxial accelerometer devices with the wavelet-based activity classification algorithm were selected based on their better performance over the other options. Clinical Trial 2 addressed the diagnostic accuracy efficacy level. This trial was aimed to determine the accuracy of the wavelet-based algorithm in detecting movements of older patients. Validation data were collected from 10 geriatric rehabilitation patients while they performed a standardised activity routine. The wavelet-based algorithm was found to have a low sensitivity (63%) for stand-to-sit transitions, therefore improvements to the algorithm were required. Clinical Trial 3 addressed three levels of efficacy: technical, diagnostic accuracy and diagnostic thinking efficacy. Twenty patients were attached with the device everyday during their waking hours until discharge. Their activity data were not disclosed to clinicians. The first aim of this trial covered the technical efficacy level, which was to determine the device acceptability by patients and nursing staff. Feedback of the device were mostly positive, where most patients were happy to wear the device in hospital, and most nursing staff reported that the device was easy to put on and practical for patients to wear. The second aim covered the diagnostic accuracy efficacy level, which was to collect more development data to improve the accuracy of the algorithm. An upright angle algorithm using development data collected from patients was implemented to replace the wavelet-based algorithm. This algorithm performed better than the wavelet-based algorithm, and has a sensitivity and specificity of greater than 89% for each of the activity category (lying, sitting, standing, walking, sit-to-stand and stand-to-sit transitions). The third aim covered the diagnostic thinking efficacy level, which was to determine whether clinicians were aware of their patient’s mobility level. Clinicians were asked to estimate the average amount of walking for each patient in the previous week, and these estimates were compared with the device measurements. A majority of the clinicians overestimated the amount of walking by an average of 2.64 times of that measured by the devices, and less than 40% of the clinicians’ estimates were within 15 minutes of the device measurements. Clinical Trial 4 assessed the diagnostic accuracy and therapeutic efficacy of accelerometry in activity monitoring. This trial was aimed to validate the algorithm with a new set of test data that was not used in the development of the algorithm, and to determine whether providing patient’s activity information to clinicians in the form of weekly activity reports can influence clinical decision making to promote more walking activity. Results showed that the algorithm was able to classify movements of older patients accurately with a sensitivity of >78% and a specificity of >93% for all the activity categories. Feedback from clinicians on the activity reports was mostly positive. In 88% of the surveys, clinicians reported that the activity reports were useful in determining patient’s progress, and 71% agreed that the reports were able to motivate them to increase patient’s activity level. This dissertation provides evidence for the efficacy of accelerometry in activity monitoring. In particular, it is acceptable for both patients and nursing staff; it can accurately measure the activities of older patients; it can provide activity information of patients that were previously unknown to clinicians; and the activity information can motivate clinicians to promote patient’s activity levels. More research is required to address the patient outcome efficacy and the societal efficacy. This includes whether providing activity information to clinicians and patients can increase activity levels via explicit goal setting, and constructing a cost benefit analysis on using accelerometry in rehabilitation settings.2011-12-11T18:31:51Z
Vivian Hoi Yee Cheung Quantitative assessment of myocardial systolic function using echocardiography
http://espace.library.uq.edu.au/view/UQ:106318
2007-08-24T18:09:08Z
Cain, Peter Anthony. Quantitative evaluation of hepatic morphological alterations and pharmacokinetic changes of cationic drugs in fibrosis-inducing hepatic diseases
http://espace.library.uq.edu.au/view/UQ:105929
2007-08-24T17:53:43Z
Chang, Ping. Quantitative studies on the effects of a number of factors which influence the distribution of fungi in soil and rhizospheres
http://espace.library.uq.edu.au/view/UQ:259581
2011-10-25T15:33:02Z
Aberdeen, J. E. C. (John Errol Chandos) Quantitative virtual microscopy for diagnostic pathology
http://espace.library.uq.edu.au/view/UQ:329134
2014-05-01T20:55:19Z
Altinay, Doreen Quantum-Atom Optics and Dynamical Simulations of Fermionic Many-Body Systems
http://espace.library.uq.edu.au/view/UQ:243224
Abstract The measurement and characterisation of correlation functions has recently become one of the central themes in the studies of ultracold quantum gases. By probing complex many-body states of these interacting systems, correlation functions facilitate the most in-depth understanding of the underlying physics, not accessible through simple density profile measurements. In this thesis, we study the dynamics of second-order correlation functions for atoms created in pair-production processes such as molecular dissociation and atomic four-wave mixing. More specifically, in Chapter 3 we analyse the dynamics of correlated atom pairs created via controlled dissociation of a Bose-Einstein condensate of diatomic molecules. The atomic constituents can be either a pair of bosonic or fermionic atoms. The process provides a matter-wave analog of parametric down-conversion with photons, which was pivotal in the advancement of quantum optics by enabling experimental
demonstrations of the famous Einstein-Podolsky-Rosen paradox and violations of a classical Bell inequality. The atom-optics analogues of parametric down-conversion make it possible to envisage similar demonstrations using ensembles of massive particles in quantum gas regimes. In the case of fermionic constituents, molecular dissociation offers the possibility of a new paradigm in fermionic quantum-atom optics. By aiming at experimentally realistic modelling, we examine the role of spatial inhomogeneity of harmonically trapped molecular condensates on the strength and the shape of atom-atom correlations. Using the undepleted molecular-field approximation, we obtain explicit analytic results for the short-time asymptotic behaviour of the second-order correlation functions and for relative number squeezing between the dissociated atoms in one, two, and three spatial dimensions. Comparisons with the numerical results, which incorporate the molecular depletion and s-wave scattering
interactions, show that the analytic approaches employed here capture the main underlying physics and provide useful insights into the dynamics of dissociation for conversion efficiencies up to 10%. The results show explicitly how the strength of atom-atom correlations and relative number squeezing degrade with the reduction of the size of the molecular condensate. In Chapter 4, we study highly anisotropic molecular condensates in order to quantify the effects of bosonic stimulation and fermionic Pauli blocking on the dissociation dynamics. We show that the difference in quantum statistics of the atomic constituent is manifest as complementary geometric structures in the density profiles of the dissociated atoms. Atomic bosons are preferentially emitted along the long axis of the molecular condensate due to bosonic stimulation, while atomic fermions are preferentially emitted along the short axis due to Pauli blocking. This anisotropy potentially simplifies the measurement of
correlations between the atoms through relative number squeezing. In Chapter 5 we apply our analytic approaches to a related problem of atomic four-wave mixing and analyze atom-atom correlations in the s-wave scattering halo of two colliding condensates. The results in the short-time limit are in agreement with the first-principles simulations using the positive-P representation and provide analytic insights into the experimental observations of Perrin et al. [Phys. Rev. Lett. 99, 150405 2007]. The final chapter of the thesis, Chapter 6, is devoted to the first application of the Gaussian fermionic phase-space method to a dynamical simulation of a multimode fermion-boson system. As a first-principles approach, the method provides benchmarking of approximate approaches and can be used to validate dynamical probes for characterizing strongly correlated phases of fermionic systems. We have applied the Gaussian phase-space method to the problem of molecular dissociation in the simplest
uniform case and demonstrated a successful treatment of large molecular condensates containing up to 10^4 molecules and 10^3 distinct atomic modes. Simulating a system in such a large Hilbert space would be impossible using a more traditional exact numerical method based on the number-state representation. Our simulations reveal, in the long-time limit, significant deviations of atom-molecule and molecule-molecule correlations from the predictions of approximate pairing mean-field theories, as well as significant departures of atom-atom correlations from Wick's factorisation scheme. We have examined the accuracy and limitations of the fermionic phase-space results by comparison with the number-state calculations for small-size systems and via the analysis of conserved quantities. Future extensions of this work will have to incorporate spatial inhomogeneity and s-wave scattering interactions in order to enable first-principles dynamical simulations of a broader class of fermionic
systems of current experimental interest. To this end, we have implemented a phase-space treatment of the Fermi-Hubbard model and present some exploratory simulations of Hubbard dynamics.2011-07-04T22:37:05Z
Magnus Oegren Quantum chaos in atom optics
http://espace.library.uq.edu.au/view/UQ:366411
2015-07-29T16:29:58Z
Dyrting, Sigurd Quantum coherence in degenerate Bose gases
http://espace.library.uq.edu.au/view/UQ:132735
The central theme of this thesis is that of coherence in bosonic matter-wave fields. Analogous to optical coherence; the measure of the capacity of a photonic beam to produce fringes upon interference; matter-wave coherence is in many ways the defining characteristic of the BEC phase of identical massive bosons. Its study therefore plays a critical role in the quest to better understand the physics of ultra-cold quantum gases, which has been the goal of this research. This work approaches coherence from a number of different angles and is for this reason presented in two parts. The first of these delves into the physics of perfectly coherent matterwave fields which are adequately described by ‘mean field’ equations, while the second is devoted to origins and repercussions of the diminished coherence evident in actual atom laser experiments. The presentation of the original work of this project begins with a detailed study of the interaction between an atomic and a molecular condensate, coherently coupled at zero temperature via one of several possible mechanisms (a Feshbach resonance, for example) in three spatial dimensions. Despite the presence of repulsive scattering interaction between the atoms, the mean-field equations of motion are known to support bright solitary waves — time-independent solutions which remain localised even in the absence of a trapping potential. (These solutions are the matter-wave analogue of spatio-temporal solitons in quadratic nonlinear media, but can also represent stationary states of the Schr¨odinger-Newton equations describing bosons interacting via a gravitational field.) Ignoring all interactions save the repulsive inter-atomic scattering mentioned, a variational ansatz approach is employed to analytically approximate these stationary solutions using Gaussian density distributions of the atomic and molecular clouds. By evolving these approximate solutions numerically, a comprehensive map of the accessible parameter space is constructed, showing primarily stable localised propagation. Parameter space regions where the approximate Gaussian solutions display strong ‘breathing’ oscillations are identified, and a modified ansatz having exponentially decaying tails is found to dramatically reduce the amplitude of these oscillations. Finally, by seeding a numerical relaxation algorithm with our Gaussian solutions, we find that the only parameter space region in which the approximate solutions diffuse under propagation is also devoid of exact localised stationary solutions. The discussion then proceeds beyond the scope of mean field theory, and turns to a detailed treatment of the quantum mechanical observable corresponding to the centre of mass of systems of identical particles. Firstly, careful consideration is given to its operational definition in the presence of fluctuating particle numbers. Possible pitfalls due to naive approximations when the number fluctuations are large are also addressed. Attention is then given to the fundamental quantum noise associated with this variable, which provides a physical mechanism for diminished first order coherence in degenerate Bose gases, even at zero temperature. Characteristic lower bounds (standard quantum limits) to the resulting mean position uncertainty are identified both for systems of identical bosons and identical fermions with comparable density profiles. Interestingly, fermions are found to have an intrinsically lower mean-position uncertainty than bosons, a fact which is attributed to the action of Pauli repulsion between atoms confined to a fixed density distribution. The results of numerical simulations of the exact quantum evolution of mean position variance are then presented. These demonstrate firstly the quantum diffusion of the mean position of one dimensional matter-wave solitons and secondly the evolution of variance in the centre of mass of a Bose gas undergoing forced evaporative cooling. Finally, attention is paid to the fact that the Penrose-Onsager criterion, which essentially equates Bose condensation with perfect first-order matter-wave coherence, fails to correctly detect the presence of BEC when a priori knowledge of the exact condensate mode is imperfect or unavailable. Insight is gained by drawing analogies between this criterion and entropic measures of entanglement between particular system subspaces. This motivates employment of the concept of entanglement of formation as a means to providing a more accurate measure of condensation in the general case of mixed system states. Unfortunately, this new measure remains adversely sensitive to superpositions of condensate modes. For this reason, alternative criteria based on higher order particle number correlation functions are also proposed.2008-03-20T11:17:23Z
Vaughan, Timothy Quantum complexity, Emergence and Computation by Measurement : On what computers reveal about physical laws, and what physical laws reveal about computers
http://espace.library.uq.edu.au/view/UQ:184137
Any computation is facilitated by some physical process, and the observable quantities of any physical process can be viewed as a computation. These close ties suggest that the study of what universal computers are capable of may lead to additional insight about the physical universe, and vice versa. In his thesis, we explore three lines of research that are linked to this central theme. The first partition shows how notions of non-computability and undecidability eventually led to evidence of emergence, the concept that even if a ‘theory of everything’ governing all microscopic interactions were discovered, the understanding of macroscopic order is likely to require additional insights. The second partition proposes a physically motivated model of computation that relates quantum complexity, quantum optimal control, and Riemannian geometry. Thus insights in any one of these disciplines could also lead to insights in the others. The remainder of this partition explores a simple application of these relations. The final partition proposes a model of quantum computation that generalizes measurement based computation to continuous variables. We outline its optical implementation, whereby any computation can be performed by single mode measurements on a resource state that can be prepared by passing a collection of squeezed states through a beamsplitter network.2009-09-23T20:22:02Z
Mile Gu Quantum control and Quantum information
http://espace.library.uq.edu.au/view/UQ:158466
Quantum information science has blossomed into a major research field over the past decade or so. In doing so, it has established links with several other areas of physics, computer science, and engineering. One of these areas is quantum control the extension of control theory to physical systems whose dynamics are governed by quantum mechanics. Quantum control, like quantum information, is a fairly young field with remarkable technological consequences, and this cross-pollination is proving to be stimulating. In this thesis we explore some of the connections between quantum information and quantum control. In particular, (i) we examine quantum error correction from a quantum feedback control perspective, and demonstrate new continuous time implementations of quantum error correcting codes; (ii) we consider performing quantum feedback control experiments on a solid-state quantum computing architecture circuit QED and propose new measurement schemes that would enable such experiments; and (iii) we consider the problem of optimally estimating quantum processes, and in particular, analyze in detail the problem of optimally estimating a one-parameter quantum process.2008-11-21T15:40:11Z
Sarovar, Mohan Quantum Electromechanical Systems (QEMS)
http://espace.library.uq.edu.au/view/UQ:158311
Much interest has been shown lately in the physics of the electrical and mechanical interplay within a Quantum Electro-Mechanical System (QEMS). This thesis presents the study of the interaction between electrical and mechanical degrees of freedom in various Quantum Electro-Mechanical Systems, in particular the C[subscript]60 system, the shuttle system, the magnetic shuttle system and the cantilever-ion system. These systems are treated as open quantum systems. The possibility to use these systems in various setups such as an ultrasensitive displacement detector and spin detector is investigated. We describe each system by quantum master equations and derive coupled equations of motion for the electron occupation number, vibrational degrees of freedom and thermo- mechanical noise. We use the Quantum Optics Toolbox[1] to compare and contrast the well known semiclassical predictions to the full quantum dynamics. In particular, we compare the picture of ensemble averaged dynamics of various moments with a `quantum trajectory'[2] simulation of moments. Within the C[subscript]60 system, we derive the observed quantities such as conductance through the system and compare this to the experimental results previously obtained. We follow this with the analysis of the shuttle system as proposed by Gorelik [3], where a dependance of the tunnel rate on the position of the island is added. Again we include descriptions of the local system dynamics. We also look for the correlation in the current fluctuations. Adding a spin degrees of freedom, we describe the magnetic shuttle. The conductance across the junctions differs for each orientation of the spin. Here the feasibility of the application of the system as a single spin measurement is explored. By coupling a cantilever to a trapped ion, we examine the possibilities to transfer phonon excitations in a cantilever to a trapped ion with the aim to read out these phonon excitations by reading the electronic state of the ion as the phonon modes in the ion are coupled to its electronic state by a laser. The conditional evolution of the cantilever is also presented. We show that within these various system, the dynamics contains a lot of interesting physics which can be usefully employed in various applications including position sensing, spin detection and cantilever cooling.2008-11-21T15:27:04Z
Utami, Dian Wahyu Quantum estimation for gravitation and quantum information with acceleration
http://espace.library.uq.edu.au/view/UQ:274250
In this thesis we shall apply techniques from quantum information theory to the problem of measuring the structure of spacetime or equivalently measuring the gravitational field. In turn we will also look at how acceleration may effect quantum information techniques for processing and transmitting information. Measuring the structure of spacetime is a slight abuse of terminology as spacetime structure is not directly observable. We will be investigating the estimation of spacetime structure by making measurements on quantum systems which depend on the spacetime background. The structure of spacetime and the gravitational field will be treated in accordance with Einstein's general theory of relativity. This is currently the most accurately tested classical theory for gravity. It is widely believed that fundamentally, gravity should be treated within the framework of quantum mechanics, just like the other forces of nature. This is yet to be seen experimentally and a theory capable of falsifiable predictions is yet to be found. In this thesis we shall focus on the effects of gravity at the classical level, however we shall treat matter and non-gravitational energy using quantum mechanics. When looking at how gravity effects quantum information we will specifically be focusing on the simple case of acceleration, yet we shall treat it in this relativistic spacetime context. Knowing the structure of spacetime in general relativity amounts to knowing an object called the metric tensor. This object contains all the information about a spacetime. This may include local curvature, for instance around a star or black hole, gravitational radiation coming from a binary pulsar and even the large scale structure of the universe such as the rate of expansion. By performing local experiments one may attempt to extract this information. Fundamentally these experiments will be governed by quantum mechanics, hence the accuracy of the estimation will be fundamentally limited by the statistical nature of quantum theory. In this thesis we shall develop an equation which states just what accuracy one can ultimately achieve when attempting to measure the structure of spacetime. This equation will be shown to be a generalisation of known results for the accuracy to which one can ultimately measure position and momentum as well as time and energy. The result will be applied to a range of relativistic phenomena including acceleration in flat spacetime, the local curvature around a black hole, the amplitude of a gravitational wave and the expansion of the universe in a cosmological model. Following the use of quantum information theory to investigate gravity we shall look at how acceleration can effect quantum information. Firstly we shall see how quantum entanglement can be created and stored between two optical cavities when one is uniformly accelerating. This is in contrast to a number of results which predict that entanglement will be lost in the presence of acceleration. This loss of entanglement is predicted due to an as yet unobserved phenomena known as the Unruh effect. The Unruh effect states that an observer uniformly accelerating will see a thermal distribution of particles even if an inertial observer will see no particles at all. We will show how the use of optical cavities can prevent this effect from causing problems both for the storage and creation of entanglement. Finally we shall look at how a particular quantum detection scheme can be employed in the presence of acceleration. Our technique will emphasis the importance of locality, that is the localisation of physics in spacetime. We will also show how some commonly used approximations used to study the Unruh effect, can be avoided with our new formulation.2012-05-20T13:34:54Z
Downes, Tony Gregory Quantum Information and Quantum Computation with Continuous Variables
http://espace.library.uq.edu.au/view/UQ:179268
The idea to assimilate classical information theory with quantum mechanics resulted in the creation of a new field in physics known as quantum information. One of the first papers in this new field occurred in the early 1970's when Stephen Wiesner wrote the seminal manuscript titled: "Conjugate Coding". However, its importance wasn't imme- diately recognized and wasn't published until 1983. The 1980's and 1990's saw a number of important papers published in quantum information leading to the subfields of quantum cryptography, quantum teleportation, quantum entanglement, distinguishability of quantum states, and quantum cloning. It was also during the 1980's, that a new model of computing, known as quantum computation, was beginning to emerge. It offered the possibility of solving certain problems faster than a classical computer by exploiting various properties of quantum mechanics. Research in this field was undoubtedly stimulated by a well known talk given by Richard Feynman in 1981 at MIT on quantum simulations. Both quantum information and quantum computation were initially developed with quantum discrete variables in mind. However, over the course of the last decade, there has been a significant increase in using quantum continuous variables. This thesis will focus on the topic of quantum information and quantum computation using continuous variables. Specifically, we will theoretically consider the cloning of continuous-variable entanglement, the distinguishability of Gaussian states, new continuous-variable quantum cryptography protocols and finally, the universality of quantum computation using continuous-variable cluster states.2009-07-14T14:03:13Z
Christian Weedbrook Quantum interference and cavity QED effects in a V-system
http://espace.library.uq.edu.au/view/UQ:106511
2007-08-24T18:16:10Z
Akram, Uzma Quantum measurement of biology
http://espace.library.uq.edu.au/view/UQ:331886
2014-06-05T12:38:46Z
Taylor, Michael Quantum Mechatronics
http://espace.library.uq.edu.au/view/UQ:273756
This thesis studies and finds correspondences between the steady state and entanglement present in the quantum description of a dissipative nonlinear system, and the bifurcations of attractors in the steady state of the corresponding semi-classical model. The stable steady states of the semi-classical models include fixed points, single limit cycles, and multi-stability with many stable limit cycles. We show quantum signatures of bifurcations of these semi-classical steady states in the full quantum dissipative systems. Furthermore, we show that these quantum systems are realisable experimentally as nano-electromechanical devices. Recent progress in the fields of circuit quantum electrodynamics (circuit QED) and nano-mechanics means that their fabrication is possible. This thesis introduces the necessary mathematical and physical tools in Chapter 2, and introduces the experimental contexts of circuit QED and nano-mechanics in Chapter 3. The following chapters then study various nano-electromechanical devices. In Chapter 4, we consider a quarter wave coplanar microwave cavity terminated to ground via a superconducting quantum interference device. By modulating the flux through the loop, the cavity frequency is modulated. The flux is varied at twice the cavity frequency implementing a parametric driving of the cavity field. The cavity field also exhibits a large effective nonlinear susceptibility modelled as an effective Kerr nonlinearity, and is also driven by a detuned linear drive. We show that the semi-classical model corresponding to this system exhibits a fixed point bifurcation at a particular threshold of parametric pumping power. We show the quantum signature of this bifurcation in the dissipative quantum system. We further linearise about the below threshold classical steady state and consider it to act as a bifurcation amplifier, calculating gain and noise spectra for the corresponding small signal regime. Furthermore, we use a phase space technique to analytically solve for the exact quantum steady state. We use this solution to calculate the exact small signal gain of the amplifier. In Chapter 5, we consider the steady states of a harmonic oscillator coupled so strongly to a two-level system (a qubit) that the rotating wave approximation cannot be made. The Hamiltonian version of this model is known as the ExB Jahn-Teller model. The semi-classical version of this system exhibits a fixed point bifurcation, which in the quantum model leads to a ground state with substantial entanglement between the oscillator and the qubit. We show that the dynamical bifurcation survives in a dissipative quantum description of the system, amidst an even richer bifurcation structure. We propose an experimental implementation of this model based on a superconducting cavity: a superconducting junction in the central conductor of a coplanar waveguide. In Chapter 6, we consider a theoretical model for a nonlinear nano-mechanical resonator coupled to a superconducting microwave resonator. The nano-mechanical resonator is driven parametrically at twice its resonance frequency, while the superconducting microwave resonator is driven with two tones that differ in frequency by an amount equal to the parametric driving frequency. We show that the semi-classical approximation of this system has an interesting fixed point bifurcation structure. In the semi-classical dynamics a transition from stable fixed points to limit cycles is observed as one moves from positive to negative detuning. We show that signatures of this bifurcation structure are also present in the full dissipative quantum system and further show that it leads to mixed state entanglement between the nano-mechanical resonator and the microwave cavity in the dissipative quantum system that is a maximum close to the semi-classical bifurcation. Quantum signatures of the semi-classical limit-cycles are presented. In Chapter 7, using amplitude equations, we describe the classical dynamics of N nano-mechanical resonators inside a single co-planar microwave cavity. The nano-mechanical resonators are not directly coupled to one another, but an effective all-to-all coupling is mediated through their capacitive coupling to a common field mode of the microwave cavity. The coupling of each nano-mechanical resonator shifts the frequency of the cavity field proportional to the displacement of each resonator. We show that groups of identical nano-mechanical oscillators synchronise to form a single mechanical mode which couples to the microwave cavity with a strength dependent on the square sum of the individual mechanical-microwave couplings. Classically this system has a rich local and global bifurcation structure dominated by periodic orbits which, when analysed using amplitude equations, can be shown to exhibit multi-stability. Further we show that if the nano-mechanical oscillators are nonidentical the mechanism by which synchronisation is lost resembles that for large amplitude forcing which is not of the Kuramoto form.2012-05-08T12:39:30Z
Charles Meaney Quantum Nanomechanics: State Engineering and Measurement
http://espace.library.uq.edu.au/view/UQ:227119
Recently, there has been a great deal of interest in the study of mechanical systems near the quantum limit. That is, if one treats a macroscopic mechanical resonator as a damped harmonic oscillator, it is natural to ask about the quantum mechanics of such an oscillator. Can one cool the macroscopic mechanical degree of freedom to its quantum ground state, and can one monitor this degree of freedom with a sensitivity approaching the level of its quantum fluctuations? A number of experiments with a wide variety of mechanical system sizes and resonance frequencies have now approached quantum limits. Hence, one may consider the possibility of engineering quantum states of the mechanical mode. Of course, one must also detect such states, and so explicitly address the subtleties of quantum measurement in such systems. These topics are the subject of this thesis. One system that has been studied for the purpose of cooling and measurement of a mechanical resonator is a driven coplanar superconducting microwave cavity with an embedded, capacitively-coupled nanomechanical resonator. The steady-state entanglement between the mechanical mode and the microwave cavity mode, quantified through the logarithmic negativity, was calculated for driving of the cavity on the blue and red sideband of its resonance, detuned by the mechanical resonance frequency. It is shown that the steady-state entanglement persists with experimentally accessible parameters, though its verification is problematic. By adding parametric driving to the nanomechanical resonator, meaning modulation of its effective spring constant, it is possible to generate a squeezed state of the mechanical mode. In the adiabatic limit, where the cavity is effectively slaved to the mechanical mode, and under driving on the blue, red, and blue and red sideband driving of the microwave cavity, the output microwave field spectrum is calculated. The conditions under which one can infer squeezing of the mechanical motion through the observation of squeezing of a component of the output microwave field, are derived. This condition could be satisfied with the red sideband drive, which is compatible with resolved sideband cooling of the mechanical mode. To generate a highly non-classical state such as a Fock state (or number state), a highly nonlinear element must be added to the system. This could be provided by a Cooper pair box configured as a charge qubit. A Cooper pair box may be read-out using a microwave cavity, forming a circuit QED system. If the nanomechanical resonator is also dispersively coupled to the Cooper pair box, then a quantum non-demolition measurement of Fock states of a nanomechanical resonator via feedback control of the coupled circuit QED system is possible. Simulations of the measurement dynamics of such a system are performed. Projection onto Fock states of the nanomechanical resonator, and quantum jumps between these states, are observed. Beyond fundamental quantum mechanical experiments with macroscopic degrees of freedom, nanomechanical resonators may be applied for ultra-sensitive measurement. In the context of quantum metrology, the sensitivity with which some parameter may be estimated scales inversely with the number of quanta available for its measurement; this is known as the Heisenberg limit. In a nonlinear system, super-Heisenberg scalings of the parameter sensitivity are possible. The nonlinear regime is readily accessible in nanomechanical resonators. We consider the mechanical analogue of a nonlinear interferometer, formed by two electrostatically-coupled nanomechanical resonators with a Duffing nonlinearity. It is shown that the super-Heisenberg scaling of the sensitivity with which one can estimate the strain-dependent nonlinearity is achievable, and maintained in the presence of realistic levels of dissipation.2011-01-26T23:22:03Z
Matthew Woolley Quantum optics and optomechanics with microtoroids
http://espace.library.uq.edu.au/view/UQ:283755
2012-10-22T16:48:12Z
McRae, Terry Graham Quantum trajectories and feedback
http://espace.library.uq.edu.au/view/UQ:366355
2015-07-29T16:22:54Z
Wiseman, Howard Mark Quasiclassical states for the Coulomb problem and the dynamical algebra so(4,2)
http://espace.library.uq.edu.au/view/UQ:349895
2015-01-27T16:35:54Z
McAnally, David Scott Quasi-Hopf Star Superalgebras
http://espace.library.uq.edu.au/view/UQ:152743
2008-08-20T09:31:56Z
Lekatsas, Tel Queens, Dames, and Blokes in Frocks: Redressing Transgender in Australian Television and Film
http://espace.library.uq.edu.au/view/UQ:322222
2014-02-05T10:11:02Z
Mcintyre, Joanna R. Queensland Caesar: Sir Thomas McIlwraith
http://espace.library.uq.edu.au/view/UQ:133066
For twenty-two years, between 1870 and 1896, Sir Thomas McIlwraith served as a Member of the Queensland Legislative Assembly. He was thrice Premier of Queensland and held various ministerial positions including Colonial Treasurer. He was an engineer, visionary, politician, businessman, entrepreneur, pastoralist and family man. Biographers have neglected McIlwraith although they have written substantial accounts about other colonial leaders, including a full-length biography of Sir Samuel Griffith, the other significant colonial figure of the epoch. This biography on the life of McIlwraith assesses his political, business and private life and contends that he espoused a classical liberal political philosophy throughout his life. McIlwraith was a liberal and not a conservative as portrayed by historians. A proud Scotsman, he inherited a radical liberal and Covenanting background and became a classical laissez-faire liberal. Apart from Adam Smith the influence of John Mill is evident in McIlwraith’s beliefs. Under the influence of Mill he became a mild protectionist to allow for the establishment of new, colonial industries. After study at the University of Glasgow, where he witnessed progress and the Industrial Revolution, McIlwraith arrived in Melbourne in 1854 and became a civil engineer on the Victorian Railways. A pastoralist in Queensland in 1870, McIlwraith was elected to the Queensland Legislative Assembly in that year. As Premier from 1879, McIlwraith’s policies brought economic development and prosperity to Queensland. He championed Queensland’s growth and development while he promoted his own self-interests. His focus was for the economic development and settlement of Queensland through the construction of railways. He established a direct steamship service for mail, freight and immigrants from London to Queensland and, in April 1883, attempted annexation of eastern New Guinea, which became the impulse for Australian federation. In mid-1883 he sought the construction of a transcontinental railway from Charleville to the Gulf of Carpentaria, which led to his election defeat. He held the Premiership briefly again in 1888 and 1893 before paralysis, diagnosed as peripheral neuritis, forced him to resign. In 1890, he formed a coalition government with Griffith, his bitterest enemy of the previous decade. Politics, his first passion, deprived him of time for his businesses. McIlwraith’s investments collapsed with the fall in asset values after the 1893 bank crash and depression, low wool prices and cattle tick infestation. McIlwraith was ill in London when the report into the collapse of the Queensland National Bank was being prepared by the Committee appointed by parliament. When the report was tabled in parliament, he was accused of a partnership with Drury, the late general manager of the bank. Although McIlwraith owed the bank £251,461 against security of £60,700, it was his partnership as a senior Minister of the government with Drury that became the central issue. Castigated by the rising Labour Party and union movement as a capitalist, McIlwraith was seen as a swindler, an anachronism of another time, as he was made the scapegoat for the bank’s insolvency by the government. His social conscience had not developed from his formative years as he had failed to appreciate the change in community values. His classical laissez-faire liberal philosophy that he had inherited remained embedded in every aspect of his life. In 1900, he died in London and was buried in Ayr, Scotland.2008-03-28T10:08:11Z
Beanland, Denver Queensland Rifle Association 1861-2011
http://espace.library.uq.edu.au/view/UQ:270326
In April 2009, the Queensland Rifle Association (QRA) commissioned: 1. a written history of the association (approximately 20,000 words), 2. the development of an archive for the QRA 3. the introduction of an oral history archive 4. the introduction of a cataloguing system for the archive 5. an exhibition using archival material for the 2011 World Championship to be held at Belmont Range The history covers the Association’s inception and development over one hundred and fifty years from 1861 to 2011. It adds a full century to the previously published work, Lt-Col A. T. Jackson’s Southern Queensland Rifle Association Jubilee 1877-1927: a brief history of the association during the past fifty years. Jackson’s account is strong on sporting detail but never clarifies any decision the QRA had taken. The new commissioned history therefore explains the QRA’s evolution, and situates the association’s growth in a social, cultural and political context. By including appropriate local, national and international background, the history analyses the association’s changing roles: an offshoot of British imperialism, a conduit for Australian nationalism, a contributor to Australian defence and a social hub for its members. A draft was delivered to the publishers in March 2011, and the book, Home on the Range: Queensland Rifle Association 1861 – 2011, was launched by the Governor of Queensland at the QRA’s Queen’s Prize meeting in mid August 2011. The QRA now has an archive storage room at the Belmont Range, Brisbane. The oral history program includes interviews with the QRA’s three oldest members, Arthur Penwarn, Jim Rush and Alastair McPherson. The cataloguing system is simple, flexible and capable of online data input from various localities, including at-home data entry. The exhibition is now on display at the QRA’s Belmont headquarters in the reception room, immediately adjacent to the archival storeroom. The QRA History Committee and supervisors from the School of History, Philosophy, Religion and Classics at the University of Queensland jointly managed the project.2012-03-18T20:28:13Z
William Casey Queer spectacles: Sex between straight men in Australian political cartoons 1992 - 2009
http://espace.library.uq.edu.au/view/UQ:229850
2011-02-22T14:12:14Z
Simon Astley Scholfield Query Answering for Multiple Complex Resources: Description Logic in the Semantic Web Context
http://espace.library.uq.edu.au/view/UQ:158314
The Semantic Web is a collection of many different data pages. It is still unclear how to answer a query posed on the Semantic Web using formal methods. Currently, the main approach to the above problem is addressed by description logics. However, description logics treat the Semantic Web as a single assertional knowledge base, based on a single ontology. In general, many web pages are irrelevant for a given query. Consequently, data retrieval services in description logic systems can be inefficiency if straightforward retrieval algorithms are chosen. In this work, we propose a space reduction methodology to address this issue. In particular, we develop techniques aimed at the reduction of the search space a description logic reasoning algorithm needs to take into account for answering a query. To reduce the search space, we need to be able to identify: 1) the dependency between pairs of Semantic Web data sources in order to maintain soundness of reasoning, and 2) the data sources which are fully irrelevant. Thus we need a way to determine whether a data source is relevant with respect to a query. Consequently, each data source must be associated with its source description. We propose a specification of source description and show how it can be used to reduce the reasoning search space. It has been argued that reasoning on the Semantic Web will benefit from the addition of rule systems to description logics. Accordingly, we specify how to combine rule systems, in particular defeasible logic, to description logics, and compare the expressivity of the rule system and the description logic system. We choose defeasible logic since, to the best of our knowledge, it is the only nonmonotonic reasoner that can operate in PTime. A nonmonotonic rule system gives us the ability to handle incomplete information in an easier way than description logic systems. We also extend the proposed space reduction method to the logic resulting from the combination of defeasible and description logic, defeasible description logic (DDL). The results from this PhD research allow one to find the answer of a complex query from a description logic-based, single ontology, Semantic Web system. Furthermore, the efficiency of description logic-based query answering also benefit from this research, and so the efficiency of rule-over description logic-based query answering.2008-11-21T15:27:34Z
Pothipruk, Pakornpong Query error detection: using base rates to improve end user query performance
http://espace.library.uq.edu.au/view/UQ:106806
2007-08-24T18:26:12Z
Robb, David A. Query processing in multiresolution spatial databases
http://espace.library.uq.edu.au/view/UQ:300075
2013-05-14T09:00:45Z
Prasher, Sham Questioning the envelope concept : thermal simulation for urban and suburban built environments
http://espace.library.uq.edu.au/view/UQ:106142
2007-08-24T18:02:54Z
Gokhale, Medha Questions to Answers
http://espace.library.uq.edu.au/view/UQ:177409
The University of Queensland Abstract Questions to Answers by Yaron Lifschitz The thesis, Questions to Answers, comprises two parts: a book-length collection of poems by the same title and a critical essay entitled “Behind the Verse: the Critical Prose of Poets” which examines critical prose written by three contemporary poets – Louise Glück, Anne Carson and Derek Walcott. The collection of poems is a series of lyrical digressions – oscillating between intimate reflections and intellectual musings. It aims to interrogate and undermine the known with pertinent (and sometimes impertinent) questions. The title suggests that rather than beginning with questions and moving to answers; the opposite journey is undertaken – the poems begin with the answers – received wisdoms, commonplace observations – and move towards uncertainty and curiosity. The poems range from short, lyrics to extended sequences. Being highly personal and eclectic statements of my sensibility, I aimed to create a free-flowing structure that reflects the curious digressions of this sensibility. There are several categories of poems that run through the work. These include poems of love and loss; short, lyrical odes to heroes of mine (mainly composers and poets); poems about reading the classics; poems about abstract philosophical musings; and poems about family – including my young son and my recently deceased sister. The placement of these poems aims to give a sense that these subjects are not distinct; reflecting my belief that one no more leaves the world of the heart to read the Odyssey than one forgoes one’s fascination with Kant to fall in love. The critical essay explores the relationship between the poetry and critical prose of three poets I admire – Derek Walcott, Louise Glück and Anne Carson. It proposes that the critical prose of poets is a neglected genre – full of delight and insight into the minds of the poets in question. The first chapter focuses on how a small observation in an essay by Walcott reveals a key feature of his poetics. The second explores the functioning of Glück’s stylistic reticence as she admires the sparse works of George Oppen. The third chapter looks at Carson’s radical troubling of the line between poetry and prose and seeks to explore it using digressive techniques borrowed from Carson herself. I begin the essay by exploring how the imperative to write a prose component to complement my poetry gave rise to this subject and finish the essay by analyzing what I learnt from its writing.2009-05-04T20:32:00Z
Yaron Lifschitz QUKU: A Mixed Grain Dynamically Reconfigurable Architecture for High Performance Computing
http://espace.library.uq.edu.au/view/UQ:159940
2008-12-23T17:55:47Z
Shukla, Sunil "WE WALK INTO THE FUTURE BACKWARDS" A CASE STUDY OF MAORI PERCEPTIONS OF THEIR ECONOMIC ACTIVITY
http://espace.library.uq.edu.au/view/UQ:158494
My thesis analyses what is generally accepted in Western European societies as the "work ethic" and compares it with Maori people's motivations to work in New Zealand. I show that ideational systems, which direct people's expectations and perceptions about work, are comprised of shared ideas, values, beliefs, rules, and meanings that are expressed through social institutions. Ideational systems also influence the ways in which people organize their workplaces, which are, in turn, a sub-system of their broader society. I argue that industrial relations are, therefore, culturally shaped rather than solely determined by technological, industrial, or political considerations. Changes in societies, due to industrialization and technological innovation, do occur but they do not necessarily converge because actors in various social systems drive and adapt to social change in culturally specific ways. I used qualitative research methodology to interpret and describe the data presented to me by informants in interviews and through questionnaires in order to construct a detailed description and understanding of variations in attitude to the concept of work of culturally different peoples. My research was conducted in New Zealand during a period of significant change in the labour market. It shows how transformations in the labour market did not coincide with changes in people's ideas about work, in particular that the ideational constructs of Maori people's work contrasted greatly with those of mainstream New Zealanders (Pakehas). It demonstrates the distinctive individualistic ways of thinking about work in Western ideational systems as opposed to the holistic and all encompassing whanau principle that informs Maori ideational systems, actions, and economic development that frames industrial relations. It shows clearly that the ideational systems are separate and that rather than conforming to the integration efforts of consecutive New Zealand governments, Maori people have embarked on a course of self-determination that is shaped by their "culture".2008-11-21T15:52:55Z
Welch, Ruby Racemization and oxygen exchange studies on some chromium (III) complexes
http://espace.library.uq.edu.au/view/UQ:345467
2014-11-19T14:09:37Z
Kane-Maguire, Noel Andrew Patrick Radar Target Recognition based on Ultra Wideband Transient Electromagnetic Scattering
http://espace.library.uq.edu.au/view/UQ:155370
2008-09-26T14:59:42Z
Antony Lui Radiation chemistry of polyesters
http://espace.library.uq.edu.au/view/UQ:365819
2015-07-29T15:10:40Z
Babanalbandi, Ahmad Radiation effects in polymer systems
http://espace.library.uq.edu.au/view/UQ:347133
2014-12-12T09:09:00Z
Garrett, Ridgnel Wayne Radiation induced grafting of expanded fluoropolymer materials
http://espace.library.uq.edu.au/view/UQ:323828
2014-02-23T02:41:00Z
Mohd Hidzir, Norsyahidah Radiation-induced solid-state polymerization of derivatives of methacrylic acid.
http://espace.library.uq.edu.au/view/UQ:215382
2010-08-31T12:21:57Z
Bowden, Murrae John Stanley. Radiation in low density hypervelocity flows
http://espace.library.uq.edu.au/view/UQ:267760
The nonequilibrium radiative heat transfer in low density, hypervelocity flows is investigated. The X2 facility at the University of Queensland was modified to allow experimentation at low pressures in nonreflected shock tube mode, characteristic of high altitude flight. Experiments were completed in a Titan mixture (98% N2, 2% CH4) at pressures of 13, 8, and 4 Pa and shock speeds of 6.4, 6.2, and 9.0 km/s respectively. Spectral measurements demonstrated a significant improvement in flow quality when compared to results from other facilities - producing test flow at such low densities, increasing the length of test gas available, and improving the signal-to-noise ratio of the spectral data.2012-02-15T23:07:13Z
Carolyn Jacobs Radiation measurements in a simulated Mars atmosphere
http://espace.library.uq.edu.au/view/UQ:282446
2012-09-25T15:19:43Z
Eichmann, Troy Nicholas Radiation of Monorchiid Trematodes in Association with Chaetodontids in the Tropical Indo-West Pacific
http://espace.library.uq.edu.au/view/UQ:260350
I report 23 species of Hurleytrematoides from seven sites in the tropical Indo-West Pacific (TIWP): Heron Island (Queensland), Lizard Island (Queensland), Swain Reefs complex (Queensland), New Caledonia, Palau, Ningaloo (Western Australia) and Moorea (French Polynesia). Nineteen are described by morphology, three are morphologically cryptic, and one has only been detected by the use of molecular data. I named fifteen new species: H. boucheti n. sp., H. combesi n. sp., H. deblocki n. sp., H. dollfusi n. sp., H. euzeti n. sp., H. faliexae n. sp., H. galzini n. sp., H. justinei n. sp., H. kulbickii n. sp., H. loi n. sp., H. moorensis n. sp., H. morandi n. sp., H. pasteuri n. sp., H. planesi n. sp., and H. sasali n. sp. Five species (H. bartolii, H. coronatum, H. fijiensis, H. prevoti, and H. zebrasomae) have been previously recorded at other Indo-Pacific localities, and three species have not been formally described. Twenty-two species are found only in the family Chaetodontidae (butterflyfishes), and one was found only in the Tetraodontidae. The Chaetodontidae was examined intensively; the study reports on examinations of 2866 individuals of 45 species of chaetodontids collected between 1986 and 2009. The 19 morphological species of Hurleytrematoides considered here comprise a complex distinguished by a single testis, bipartite seminal vesicle, unipartite terminal organ, and filamented eggs; the arrangement of the terminal genital is the key feature in diagnosing species. I collected sequence data from the internal transcribed spacer (ITS-2) region (nuclear ribosomal DNA), and the cytochrome c oxidase subunit I (CO1) gene (mitochondrial DNA). ITS-2 sequences yielded 38 haplotypes corresponding to 16 morphological species, and CO1 sequences yielded 63 haplotypes corresponding to 15 morphological species. For morphological species, intraspecific variation for both nuclear and mitochondrial regions was low within localities (with the exception of H. loi n. sp. and H. sasali n. sp.), but high between localities (up to 4.4% for ITS-2; up to 13.6% for CO1), and overlapped with levels of interspecific variation (1.6–16% for ITS-2; 9–22.7% for CO1). The high level of mitochondrial and nuclear sequence variation within three morphological species indicates that each represents a pair of cryptic species that can only be identified using molecular analysis; two pairs of cryptic species have not yet been separated as pairs of named species because holotypes cannot be designated for them. One cryptic species, morphologically indistinguishable from H. coronatum, is named (H. moorensis n. sp.). The variation in mtDNA sequences shows that regional endemism is widespread, and that there is limited gene flow between sampling localities. This implication dovetails with the results of cluster analysis done on 18 morphological species of Hurleytrematoides at six TIWP localities. The low similarity found in the Hurleytrematoides species assemblages in overlapping ranges of chaetodontids between the “Coral Sea localities” (Heron Island, Lizard Island, and New Caledonia) and Ningaloo, Moorea, and Palau was interpreted as evidence of restricted dispersal capacity over large distances, and attributed to the lack of mobility of larval trematodes that mature in site-attached fishes in the marine environment. The fact that only one species (H. morandi n. sp.) was found at all six major collecting sites, and that many species are absent from apparently suitable sites, also highlights the role of chance in dictating the distribution of marine parasites with limited dispersal. This study demonstrates the necessity of integrative taxonomy, in which multiple types of data are used to create species descriptions, and the importance of mtDNA markers in studies of digenean biogeography, which have traditionally relied on ribosomal DNA to infer taxonomic relationships in the TIWP.2011-11-02T13:09:27Z
Marissa McNamara Radiation signal transduction in ataxia-telangiectasia
http://espace.library.uq.edu.au/view/UQ:366362
2015-07-29T16:23:46Z
Beamish, Heather J Radical Restructuring: Autonomies in Italian Architecture & Design, 1968-73
http://espace.library.uq.edu.au/view/UQ:332989
2014-06-19T15:56:21Z
Brown, Alexandra Radio studies of southern interacting galaxies
http://espace.library.uq.edu.au/view/UQ:246805
2011-08-31T13:30:38Z
Gordon, Scott Douglas Radio studies of the lower ionosphere
http://espace.library.uq.edu.au/view/UQ:349662
2015-01-23T11:43:13Z
Thiele, David Lewis RAFT-mediated polymerization in nanoreactors
http://espace.library.uq.edu.au/view/UQ:289088
2013-01-14T17:16:47Z
Sebakhy, Khaled Omar Railway rolling noise prediction and validation
http://espace.library.uq.edu.au/view/UQ:332014
2014-06-09T00:20:41Z
Jiang, Shijie