In this thesis, I discuss coherent manipulation of a trapped ytterbium ion using long wavelength radiation and the results of experiments towards the performance of a two-ion entanglement gate using a static magnetic field gradient of 23.3(6) T/m to create coupling between an ion's internal state and its motion. After using these experiments to explain the requirements for high-fidelity entanglement operations, I continue by examining existing methods for creating this gradient, the current limiting factor in producing the highest fidelity operations. This includes a full characterisation of the gradients produced by symmetric scheme permanent magnets and buried current carrying wires including development of scaling laws in order to create optimum gradients for a given trap geometry. I continue by proposing a new method by which extremely high gradients over 100 T/m can be created for planar chip traps with minimal modification to an existing experiment. These gradients are tailored for axial as well as radial entanglement schemes and aim to show that the technology exists in order to produce a two-qubit gate over the fault tolerant threshold. Subsequently, I discuss the implementation of this new scheme in an experiment before constructing the apparatus to accurately align a chip with these magnets and documenting their installation into two new experimental setups. This includes a preliminary measurement of the gradient produced by an imperfect setup outside of vacuum which verifies those simulated at ~ 110 T/m. Lastly, I discuss the prospects of on-chip magnetic materials and propose a new method which when sufficiently developed should allow for high magnetic field gradients to be produced on-chip at higher ion heights than when solely using current carrying wires. Additionally this scheme should allow for switchable gradients with maximised stability in geometries previously not possible to create.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Environmental Sciences." Includes bibliographical references (p. 117-120).

Thesis (M.S.)--University of Nevada, Reno, 2006. / "May 2006." Includes bibliographical references. Online version available on the World Wide Web.

A thin-lens beta-ray spectrometer has been modified for collection of beta-rays at the position of the ring focus. This has increased the gathering power/line width ratio from ∽ 0.12 to ∽0.8. The focusing properties of the instrument have been investigated for various geometries. Using the modified spectrometer, the decay scheme of Sb 125 - Te 125 has been investigated. The primary beta spectrum, photoelectron spectra and beta-gamma coincidence spectra have been measured. From conversion coefficient measurements, the following radiative transition multipolarities were determined (energies in kev): 176(E2+M1), 428(E2+M1), 464(E2), 602(E2+M1) and 638(E2). Five primary beta groups have been identified with end point energies of 626, 450, 307, 246 and 133 kev. Previously unobserved transitions of 76, 143, 219, 355, 540 and 640 kev have been identified. Based on all experimental evidence the following states of Te 125 with spin and parity assignments have been proposed: ground state (S1/2+), 36 kev (d₃/2+), 145 kev (h₁₁/₂-), 321 kev (9/2-), 464 kev (5/2+), 525 kev (11/2- or 9/2-), 540 kev (11/2- or 9/2-), 638 kev (5/2+) and 676 kev (spin and parity undetermined). / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The nuclear energy levels of As⁷⁵ have been investigated through the study of the Se⁷⁵ decay scheme. The internal conversion spectrum as well as the photoelectron spectra (using bismuth and lead radiators) were measured with a modified thin lens magnetic spectrometer. A technique was developed for accurate determination of the transmission of the spectrometer in order to obtain the absolute conversion electron transition intensities. The gamma ray intensities were determined from the spectrum measured with a NaI(T1) scintillation spectrometer in conjunction with the results from the photoelectron spectra. From these measurements the absolute conversion coefficients for eight transitions were obtained. In addition coincidence techniques employing a slow- fast coincidence system (resolving time 10⁻⁷ sec) were used to measure gamma-gamma coincidences, conversion electron-gamma coincidences and gamma-gamma directional correlations. A one hundred channel kicksorter was used to facilitate accumulation of the data at the relatively low coincidence counting rates. Multipolarities of the following transitions were determined, (energies in kev), 97(E2); 121(El); 136(El); 199(M1+E2); 265(Ml,-0.12<δ(E2)<+0.07); 279(M1+E2, δ =-0.46 ±0.16); 304(E3) and 401(El). Also detected but for which multipolarities could not be determined was a 66 kev transition and a very weak 572 kev gamma transition. In addition the existence of a 24 kev and a 77 kev transition was inferred from the intensity measurements. An energy level diagram for As⁷⁵ has been constructed with the following energy levels and spin assignments, (energies in kev), 572 (7/2 +), 477 (?), 401 (5/2 +), 304 (9/2 +), 279 (5/2 -), 265 (3/2 -), 199 (1/2 -), 0 (3/2 -). It was concluded that the ground state of Se⁷⁵ has even parity. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Call number: LD2668 .T4 1959 M87

Thesis (Ph.D.) in Physics--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 94-99).

Thesis (M. Phil.)--University of Hong Kong, 1989.

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