Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"thermalisation"”.
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Production and excitation of cold Ps for anti-H formation by charge exchange: towards a gravitational measurement on antimatter
… a classical model of positronium production and thermalisation in NCPs and validating it by testing it against the available experimental data. In chapter 2 we describe the measurement of the energy spectrum of positronium produced by nanochanneled plates using the beam produced by the SURF …
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Adiabatic processes, noise, and stochastic algorithms for quantum computing and quantum simulation
… context of adiabatic state preparation and the thermalisation of the energy introduced to the system. We identify regimes where introducing certain type of noise in experiments would improve the final fidelity of adiabatic state preparation, and demonstrate the robustness of the state …
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Dynamical aspects of quantum information and classical simulability
… simulable (free-fermionic) setup, a deep form of thermalisation. Conventional quantum thermalisation asks whether, at late times under unitary dynamics, a small subsystem's physical observables attain thermal expectation values. However, current quantum simulators enable access to the entire …
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Overcoming Efficiency Limits in Photovoltaic Devices
… as they cool to the bandedge, a process known as thermalisation. Carrier multiplication offers a means of reducing thermalisation losses using a system in which excess energy from one electron-hole pair is transferred to produce a second electron-hole pair. Fully harnessing carrier multiplication …
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Open and Hidden Charm Mesons at Finite Temperature from Anisotropic Lattice QCD
… well understood. Due to its large mass and long thermalisation time, the charm quark is an excellent tool with which to probe the plasma. In this thesis I study the dissociation of open and hidden charm mesons. Lattice QCD provides a non-perturbative means of studying the spectral quantities of …
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Nanoelectronic and nanomechanical devices for low temperature applications
… below 4mK overcoming the challenge of electron thermalisation for on-chip devices. Mechanically vibrating devices can directly probe bulk and surface fluid properties. We developed practical measurement techniques and analysis methods to demonstrate the use of nanomechanical resonators, which …
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Dynamics of impurities and trapped Bose-Einstein Condensates
… features, and gain an understanding of the thermalisation process in such systems.
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Investigating the Photophysics of New and Stable Singlet Fission Materials
… efficiency of solar cells by reducing losses to thermalisation. Consequently, new singlet fission materials, particularly those with better photostability, are of great interest. We have drawn our conclusions by studying three novel singlet fission systems: TIPS-tetrabenzo[a,c,l,n]pentacene …
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Experimental investigations of excited-state dynamics in conjugated polymers using time-resolved laser spectroscopy
… the polymer backbone in the excited-state after thermalisation. Polarised measurements are used to demonstrate a fundamental relationship between the vibrational mode of the polymer through which fluorescence occurs and the corresponding fluorescence polarisation. Time-resolved measurements …
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The electronic transport properties of undoped and doped arsenic triselenide
… structured N(E) and a computer simulation of the thermalisation process was developed in order to obtain N(E) from the data. For sputtered material a feature incorporated at E<sub>3</sub> in a continuous tail of states gave the the best fit to the data. Determination of N(E) using two other …
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Quenching normal Bose gases to Unitarity
… that this elliptic flow is intimately linked to thermalisation, and show that it is highly dependent on the microscopic details of the collisions involved. The other experiment addresses the two- and three-body contacts in the Bose gas. These contact parameters arise from the corresponding two- …
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Spectroscopic Study of Triplet Exciton Dynamics at the Hybrid Organic-Inorganic Interface
… the Shockley–Queisser limit by overcoming the thermalisation and absorption losses inherent to all single-junction photovoltaics. Such spectral management technologies have been predicted to increase the maximum possible efficiency of Si-based cells from 32 % to greater than 40 %, breaking the …
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Synthesis and Optical Characterisation of Diphenylhexatriene Derived Intramolecular Singlet Fission Materials
… the bandgap of the semiconductor is lost to thermalisation. Singlet fission (SF) is a physical process in certain organic materials that enables the production of two excited states, each with triplet multiplicity, from a lone photoexcited singlet state. It has been widely recognised that …
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Tuneable homogeneous Bose fluids close to and far from equilibrium
… only role of weak interactions being to ensure thermalisation. We show that this ideal gas effect is robust to the influence of weak interaction energy and suggest realistic experimental conditions for the observation of the cooling and purification. Second, we describe our simultaneous …
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FUNDAMENTAL AND APPLIED MEASUREMENTS IN ICP-MS
… in an enhancement of analyte signals due to the thermalisation of the ion beam. The ion kinetic energy of ions sampled from the plasma and those sampled from the skimmer cone were determined using a modified lens stack to assess the significance for memory effects of material deposited on the …
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Coherence and Singlet Fission of TIPS-Pentacene Probed by Two-dimensional Electronic Spectroscopy
… devices by reducing energy loss through thermalisation. We use dilute solutions of TIPS-Pn to characterise the singlet states of TIPS-Pn when SF is absent. We observe coherence at 295 cm−1, 520 cm−1, 781 cm−1, 940 cm−1, 1159 cm−1 and 1341 cm−1 with lifetimes from 0.5 ps to 1.5 ps. The 940 …
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Quantitative Extraction of Bias Stress Parameters in Thin Film Transistors
… as a function of stressing time. Then a thermalisation energy analysis can be used to extract the attempt-to-escape frequency and distribution of activation energies for the bias stress process. However, previous reports have used a trial and error method for estimating the …
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Quantum simulation beyond periodicity: A theoretical study of the many-body and topological properties of quasiperiodic systems
… novel quantum phases of matter that could evade thermalisation. Solid-state quasicrystalline samples are inherently subject to defects, finite grain size, and constantly subject to atomic vibrations. Together, these effects hamper the observation of truly quantum properties caused by their …
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Quantitative measurements of temperature using laser-induced thermal grating spectroscopy in reacting and non-reacting flows
This thesis is concerned with the development and application of laser induced thermal grating spectroscopy (LITGS) as a tool for thermometry in reacting and non-reacting flows. LITGS signals, which require resonant excitation of an absorbing species in the measurement region to produce a thermal …