Exact Solutions and Scalar Fields in Gravity - Instituto Avanzado de ...

On the experimental foundation of Maxwell’s equations 301
found, so that from the accuracy of the apparatus they got the estimate
Much better estimates
result from astrophysical observations.
4.2. CHARGE CONSERVATION
Direct tests. A laboratory test of charge conservation in the sense of
looking for a decay of the electron into neutral particles has been carried
through. For this process the limit is [19]. There is also
a lot of experimental work on the neutrality of atoms which of course
proof only that the ratio of the charges of electrons and protons remains
conserved.
Time dependence of the fine structure constant. In the case of
charge non–conservation, the charge of all particles depends on time so
that especially for the charge of the electron which then implies
for the fine structure constant If we assume a
specific time–dependence of the form then Thus
experiments on the time–dependence on the fine–structure constant give
estimates on or on parts of which are not totally antisymmetric.
A measurement of a hypothetical time dependence of the fine structure
constant can be obtained by comparing different time or length
standards which depend in a different way on In the laboratory experiments
treated in [20] variations of the fine structure constant can
be detected by comparing rates between clocks based on hyperfine transitions
in alkali atoms with different atomic numbers. The comparison
of the H–maser with a Hg+ –clock resulted in so
that In a proposal [21] a monolithic resonator is employed
where the fine structure constant is related to the dispersion
in the resonator. They claim to be able to improve the estimate to
4.3. FIELD OF POINT CHARGE
In the laboratory the electrostatic field of a point charge can be measured
with very high accuracy while the magnetic field of a magnetic
moment can be determined not as good.
Cavendish experiments. The first experiment aimed to test the
inverse square law or the Coulomb potential was
carried through by Cavendish [22]. The principle of this and many following
experiments is to test the following consequence of Maxwell’s
equation: inside a metallic sphere, which has been given a certain elec-