Vector potential, electromagnetic induction and "physical meaning"

Abstract

A forgotten experiment by André Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced $emf$: the physical agent is instead the vector potential through the term $-\partial \vec{A}/\partial t$ (when the induced circuit is at rest). The "good electromagnetic potentials" are determined by the Lorenz condition and retarded formulas. Other pairs of potentials derived through appropriate gauge functions are only mathematical devices for calculating the fields: they are not physically related to the sources. The physical meaning of a theoretical term relies, primarily, on theoretical grounds: a theoretical term has physical meaning if it cannot be withdrawn without reducing the predictive power of a theory or, in a weaker sense, if it cannot be withdrawn without reducing the descriptive proficiency of a theory.

References in corpus (4)

• Historical roots of gauge invariance
• Single photon wavefront-splitting interference: An illustration of the light quantum in action
• A general law for electromagnetic induction
• Lorenz or Coulomb in Galilean Electromagnetism ?

Cited by in corpus (6)

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• Classical Yang-Mills theory in condensed matter physics
• A formal interpretation of the displacement current and the instantaneous formulation of Maxwell's equations
• Electromagnetic gauge-freedom and work
• Electromagnetic induction: how the "flux rule'' has superseded Maxwell's general law
• System-Bath Approach to Rotating Brownian Motion