  The behavior of composite matter in external fields can be very revealing.
The quantum mechanical problem of a material object (test mass) placed in a
uniform (weak) gravitational field, g, was considered by many authors starting
with Schiff [Phys. Rev. 151, 1067 (1966)]. Depending on the theoretical
treatment opposing results of gravity induced (electric) field have been
reported. In the Schiff model [L.I. Schiff, PRB, 1, 4649 (1970)] the field is
predicted to be oriented anti-parallel (with reference to g). On the other hand
it is found to be parallel in the elastic lattice model [A. J. Dessler et al,
Phys.Rev, 168, 737, (1968); Edward Teller, PNAS, 74, 2664 (1977)].
Surprisingly, modern researchers have largely overlooked this interesting
contradiction. Here an experimental test is suggested. We also reason that
advanced density functional type calculations can provide valuable guidance.
