Magnetic Moments, Fine Structure Constant, and QED

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The intellectual merit of this work derives from the possibility to make some of the most precise and fundamental measurements in physics. One goal is to make the most precise measurement of the property of an elementary particle -- the electron magnetic moment measured in Bohr magnetons. A second goal is to test the most successful and fundamental theory of physics, quantum electrodynamics (QED), to an unprecedented level of precision, arguably the most precise comparison of any theory and experiment. Quantum electrodynamics describes the interaction of matter and light, and it sets the standard to modern particle theories aspire. A third goal is to make the most precise comparison of a lepton and an antilepton (by a factor of 15 or more), the electron and the positron, as a test of CPT invariance. A fourth goal is to make the most precise determination of the fundamental fine structure constant. This constant gives the strength of the electromagnetic interaction in the low energy limit and it characterizes the size of a wide variety of phenomena, ranging from the energy scales in atoms, to the ac Josephson effect, to the quantum Hall effect. In addition, the fine structure constant is one of the crucial measured constants (along with the Rydberg and Planck's constant) for accurately determining the system of basic units that are important to a technological society rooted in science. A fifth goal is to observe the spin flip of a proton on the way to comparing the magnetic moments of the antiproton and proton a million times more accurately than has previously been possible. A sixth goal is to investigate the possibility of adapting the precision measurement methods to make the first scalable, one-electron qubit for quantum information studies. The devices and methods that will make these unusually precise measurements possible are interesting in their own right. They will include a cylindrical Penning trap cavity cooled to 100 mK, quantum nondemolition observations of one-quantum transitions of a single electron, self-excitation of a one-particle oscillator, feedback cooling, inhibition of spontaneous emission, quantum jump spectroscopy of one electron's spin and cyclotron levels and cavity sideband cooling. The experiments also offer outstanding educational opportunities. Junior participants who learned their craft doing work in this area are now engaged in research careers in various subfields of physics.