Examensarbeten för masterexamen // Master Theses
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Browsar Examensarbeten för masterexamen // Master Theses efter Program "Physics and astronomy (MPPAS), MSc"
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- PostOnline Detection of Water Vapor in an Industrial Gasifer Using Terahertz Spectroscopy(2013) Nordmark, Jens; Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap; Chalmers University of Technology / Department of Microtechnology and NanoscienceA terahertz spectrometer was set up for the monitoring of product gas in a thermal gasifer. The goal was to measure temperature and H2O concentration, and preferably also CO concentration. This environment presents several difficulties such as high temperature,toxic gases, high H2O content and a high concentration of particulate pollutants. Spectroscopy using IR Lasers tend to be obstructed by the high absorption of H2O as well as the scattering by the particulates, and so does not produce satisfactory results. It was hoped that these problems could be avoided by using terahertz radiation, with a lower absorption by water and a longer wavelength possibly avoiding scattering by particulates. A system operating in the range 300-500 GHz was built and tested in laboratory as well as in an industrial gasifer at Chalmers Power center, yielding promising results. Our results indicate that monitoring of H2O, and probably other gases, in the rugged environment of gasifer rawgas can be done with response times on the order of a few minutes. This has applications in biomass gasifcation, where variable quality of the fuel results in a need for continous monitoring and tuning of the gasification process.
- PostQuantum state tomography of 1D resonance fluorescence(2017) Strandberg, Ingrid; Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap; Chalmers University of Technology / Department of Microtechnology and NanoscienceTomography is the name under which all state reconstruction techniques are denoted, one of the most recognized examples being medical tomography. Quantum state tomography is a procedure to determine the quantum state of a physical system. By performing homodyne measurements on resonance fluorescence from an artificial atom coupled to a one-dimensional transmission line, its quantum state can be reconstructed. Resonance fluorescence is one of the simplest setups that results in non-classical states of light. If these states are non-classical in the sense that they have a negative Wigner function, they can be used as a computational resource for quantum computing. There are many different approaches to quantum computing. Some, like gate based quantum computing using discrete variables like qubits, have been extensively researched, both theoretically and experimentally. There exists and alternative approach: continuous variable quantum computing. The continuous variables we will be concerned with are the components of the electromagnetic field that constitute the resonance fluorescence. There are different parameters that affect the nature of the resonance fluorescence, for example, the number of transmission lines the atom is coupled to, or the strength of the driving field. In this work, we develop the tools necessary to numerically simulate homodyne detection of resonance fluorescence for different sets of parameters, and reconstruct the quantum state as well as calculating the Wigner negativity.