Quantum electrodynamics between conducting plates III. Relativistic theory and magnetic moment of the free electron

Abstract

We calculate the change δμ in the radiative correction to the magnetic moment μ of a free electron, when the electron is inserted between infinite perfectly conducting parallel plates. The order of magnitude is given by δμ/μ ∼ αA/ L , with a the fine structure constant, A the Compton wavelength, and L the plate separation. This contrasts with a bound electron, for which the preceding paper found δμ/μ ≈ α( A / L 2 ). Since a relativistic field theory calculation is essential for δμ, we obtain as a by-product a relativistic confirmation of the leading spinindependent energy shifts for a free electron, reported in an earlier paper.