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York University

1. Kato, Kosuke. Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium.

Degree: PhD, Physics And Astronomy, 2019, York University

The 23P1-to-23P2 fine-structure interval in atomic helium is measured using the frequency-offset separated-oscillatory-fields (FOSOF) technique. Two temporally separated microwave fields set up excitation paths that accumulate different quantum-mechanical phases. To detect the atoms that have changed states due to the microwaves, these atoms are excited to a Rydberg state and Stark ionized. The number of resulting ions is counted on a channel electron multiplier. In a typical SOF experiment, the relative phase between the two microwave pulses is toggled between 0 and 180, and the change in the signal amplitude between the two phases is detected as a function of applied microwave frequency. In the FOSOF technique, two microwave pulses with a slight frequency offset are applied to the atoms. The relative phase seen by the atoms changes continuously due to the frequency offset, leading to a sinusoidally oscillating atomic signal. The phase of the oscillating signal is measured with respect to the phase of a reference generated by combining the frequency-offset microwaves. The phase difference between the oscillating atomic signal and reference signal crosses zero at resonance and changes linearly as a function of applied microwave frequency. Major signal-to-noise ratio (SNR) enhancement has been achieved by employing a two-dimensional magneto-optical trap and by using Stark-ionization detection. The excellent SNR allows for a very extensive study of systematic effects. A wide range of experiment parameters has been investigated. The final measured result is 2 291 176 590(25) Hz. This is the most precise measurement of the interval to date and thus the most precise test of the two-electron quantum-electrodynamics theory. When the 23P0-to-23P1 transition is measured at the same level of precision and the combined result of the 23P0-to-23P2 fine-structure interval is compared with a sufficiently precise theory, a sub-part-per-billion determination of the fine-structure constant using a two-electron system will become possible for the first time. Comparison with other fine-structure constant measurements could lead to tests of possible beyond-the-Standard-Model physics. Advisors/Committee Members: Hessels, Eric (advisor), Hessels, Eric (advisor).

Subjects/Keywords: Quantum physics; helium; helium-4; fine structure; fine-structure constant; 2^3P_1-to-2^3P_2; beyond-the-Standard-Model physics; physics; atomic physics; quantum physics; FOSOF; SOF; Stark-ionization detection; precision test fundamental physics; precision; ultra-precision; precision measurement; quantum electrodynamics; Standard Model; Rydberg state; microwave; precision test of quantum electrodynamics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kato, K. (2019). Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium. (Doctoral Dissertation). York University. Retrieved from http://hdl.handle.net/10315/36266

Chicago Manual of Style (16th Edition):

Kato, Kosuke. “Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium.” 2019. Doctoral Dissertation, York University. Accessed December 04, 2020. http://hdl.handle.net/10315/36266.

MLA Handbook (7th Edition):

Kato, Kosuke. “Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium.” 2019. Web. 04 Dec 2020.

Vancouver:

Kato K. Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium. [Internet] [Doctoral dissertation]. York University; 2019. [cited 2020 Dec 04]. Available from: http://hdl.handle.net/10315/36266.

Council of Science Editors:

Kato K. Precision Microwave Frequency-Offset Separated-Oscillatory-Fields Measurement of the 2^3 P_1to-2^3 P_2 Fine-Structure Interval in Atomic Helium. [Doctoral Dissertation]. York University; 2019. Available from: http://hdl.handle.net/10315/36266

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