Historical Roots of Gauge Invariance<br> 
J. D. Jackson<br>
University of California, Berkeley<br>
and<br>
Lawrence Berkeley National Laboratory <p>


A number of reviews of gauge theories cover the period from about 1929
(Weyl's major paper on the subject) to the present day, with stress on the
post-Yang-Mills epoch. Lev Okun and I address the "pre-history" of the
subject, starting with Ampere, Neumann, Weber, and others, and the debates
over the "correct" form of the vector potential. The story continues with
Maxwell, Lorenz, Helmholtz, Clausius, and Lorentz by which time the idea of
different, equivalent gauges for the potentials in classical electromagnetism
had been clarified completely. We then discuss the annus mirabilus, 1926,
with Fock's discovery of the phase transformation of the wave function that
must accompany a gauge change of the potentials. The unfair belittlement of
the contributions of Lorenz and Fock are aired. Portraits of all the
"electricians" are presented as the story unfolds.<p>

[J. D. Jackson and Lev Okun, Rev, Mod.Phys. Vol. 73, 663- 680 (2001)]