Single Atomic Particle at Rest in Free Space: New Value for Electron Radius

Abstract

Zero-point confinement in a suitable trap is briefly discussed as a quantum-mechanical equivalent of the classical single particle at rest in free space. So far, such confinement has been realized, Fig.1, only for the 150 GHz cyclotron motion in geonium, a single electron permanently confined in a Penning trap. The most important result of stored ion spectroscopy is a new, 10 000 times smaller, radius for the electron, R < 10⁻²⁰ cm [1]. This result was obtained by analyzing our g-factor data [2], now g/2 = 1. 001 159 652 193(4), on the basis of a near-Dirac particle model, Fig.2. The best current theoretical value [3] is g/2 = 1.001 159 652 460(145). RF spectroscopy in geonium relies on the Continuous Stern-Gerlach Effect E4,53, in which a spin flip is detected as a small change in the ≈ 60 MHz axial oscillation frequency of the electron in the trap, Fig.3. The Kaufmann- Einstein Effect, or relativistic mass shift of the electron, may become a superior alternative: operating a geonium atom as a frequency selective mini-synchro-cyclotron [6] has produced an easily detectable shift in the axial frequency, Fig.4.