Computational Modeling of Hyperfine Transitions in Antihydrogen

<p dir="ltr">Antihydrogen is the simplest form of atomic antimatter and is composed of a positron and antiproton. It is analogous to Hydrogen but with opposite electric charges for its constituents, making it a powerful system for testing charge, parity, and time (CPT) symmetries. CPT symmetry predicts that the physical behavior of antihydrogen should exactly mirror that of Hydrogen. Previous experiments have confirmed antihydrogen matches Hydrogen’s physics for aspects such as charge neutrality, behavior in gravitational fields, 1S-2S transitions, and fine structure. Efforts to study antihydrogen’s hyperfine structure are ongoing, though aspects of antihydrogen’s hyperfine spectral curve remain uncertain. A better understanding of this physics yields another method for robust CPT symmetry testing at high precision.</p><p dir="ltr"><br></p><p dir="ltr">This thesis presents baseline computational simulations of the |d〉to |a〉hyperfine transition corresponding to the spin-flip of the positron. This spin-flip ejects the antihydrogen atom from a magnetic minimum trap providing a detectable event. By modeling the microwave transition, more accurate corrections to the measurement of the hyperfine splitting can be used to increase the precision of this test. Developing computational models of the |d〉to |a〉transition as a function of the injected microwave frequency relative to antihydrogen’s resonant frequency allows for better understanding of the physics behind antihydrogen’s hyperfine splitting.</p><p dir="ltr"><br></p><p dir="ltr">This system is simulated by using a Landau-Zener-like transition probability computation in conjunction with a two-level system approximation. Previously, simulations produced transition probabilities via Landau-Zener only considering contributions near resonance. As more precise simulations are required for current experiments, this method extends previous calculations by including interference effects caused by phase accumulation between the resonance regions. Results of this method show that simulations considering spatial interference effects may not be necessary and measuring antihydrogen’s hyperfine structure at a more precise scale is feasible. This method is a new computational stepping stone, providing insight into the physics necessary to consider when simulating |d〉to |a〉transitions, driving the understanding of antihydrogen’s hyperfine structure forward.</p>