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Thesis (PhD)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613873144594432 |
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| access_status_str | Open Access |
| author | Bester, Siann |
| author2 | Steenkamp, C. M. |
| author_browse | Bester, Siann Steenkamp, C. M. |
| author_facet | Steenkamp, C. M. Bester, Siann |
| author_sort | Bester, Siann |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135623 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:03.527Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135623 A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions Bester, Siann Steenkamp, C. M. Matjelo, N. J. Tame, M. S. Stellenbosch University. Faculty of Science. Dept. of Physics. Thesis (PhD)--Stellenbosch University, 2026. Bester, S. 2026. A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/4d7dc848-a519-4ba1-8fd2-9aa06760c03b Unsharp measurements belong to a class of non-projective measurements in quantum mechanics that can be described by positive operator valued measures. A series of unsharp measurements can, in principle, be used to track the dynamics of a quantum system if the measurements are realised with weak coupling so that the disturbance of the quantum system is limited. The aim of this work is to determine the feasibility conditions for the experimental implementation of unsharp measurements on trapped ytterbium ions. This is realised in two parts. Firstly, an ion trapping experimental setup was recommissioned such that trapping of both 171Yb+ and 174Yb+ was accomplished. Several systematic techniques were developed to ensure the ease and reliability of trapping within our setup. Using trapped clouds of 171Yb+, several control experiments were demonstrated. These results showcase the effects of the sideband frequency, polarisation and laser wavelength on the efficiency of Doppler cooling, state preparation and state detection. The second part of this dissertation deals with simulating unsharp measurements on these trapped ions. The aim was to simulate the unsharp measurement implementation scheme proposed by Choudhary et al. [1] on a system of two ytterbium ions (171Yb+ and 174Yb+). The simulation explicitly includes spontaneous decay processes present in the experiment, for the first time to our knowledge. By including these processes as well as accounting for realistic experimental parameters, the feasibility conditions for the experimental implementation of unsharp measurements are determined. Using this simulation, an estimation scheme is implemented which is capable of tracking an ion qubit undergoing Rabi oscillations by using only the outcomes of a series of unsharp measurements applied to the ion. We developed a method to determine convergence of this estimation scheme without knowledge of the qubit state, which can be applied in an experimental setting. This protocol was then tested under various conditions, showcasing the robustness of the protocol to experimental uncertainty and spontaneous processes. Incorporating realistic experimental parameters and uncertainties, we are able to identify the relevant time scales of qubit dynamics that could feasibly be investigated with this technique. Doctoral 2026-04-02T10:56:25Z 2026-04-02T10:56:25Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135623 en Stellenbosch University 167 pages : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Bester, Siann A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title | A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title_full | A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title_fullStr | A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title_full_unstemmed | A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title_short | A feasibility study on the implementation of unsharp quantum measurements on trapped 171Yb and 174Yb ions |
| title_sort | feasibility study on the implementation of unsharp quantum measurements on trapped 171yb and 174yb ions |
| url | https://scholar.sun.ac.za/handle/10019.1/135623 |
| work_keys_str_mv | AT bestersiann afeasibilitystudyontheimplementationofunsharpquantummeasurementsontrapped171yband174ybions AT bestersiann feasibilitystudyontheimplementationofunsharpquantummeasurementsontrapped171yband174ybions |