Gerald Gabrielse
Department of Physics, Harvard University, USA
Date
7 November 2007
Title
One-Electron Quantum Cyclotron Determines the Electron Magnetic Moment and the Fine Structure Constant
Abstract
A single electron is suspended by itself for months in the magnetic field of a Penning trap. Its cyclotron motion is cooled to the point where the quantum structure in this motion manifests itself as the energy levels of an artificial atom –the electron bound to our apparatus. Quantum jump spectroscopy of the electron's lowest cyclotron and spin energy levels reveals its magnetic moment with a precision that is much higher than was realized 20 years ago when this fundamental characte ristic of the electron was last measured. The new measurement, along with QED theory, determines the fine structure constant about ten times more precisely than any other method does.