Inequivalence Between Passive Gravitational Mass and Energy for a   Quantum Body: Theory and Suggested Experiment
  Recently, we have suggested some semi-quantitative Hamiltonian for an electron in a hydrogen atom in a weak gravitational field, which takes into account quantum effects of electron motion in the atom. We have shown that this Hamiltonian predicts breakdown of the equivalence between passive electron gravitational mass and its energy. Moreover, as has been shown by us, the latter phenomenon can be experimentally observed as unusual emission of radiation from an ensemble of the atoms, provided that they are moved in the Earth's gravitational field with constant velocity by some spacecraft. In this article, we derive the above-mentioned Hamiltonian from the Dirac equation in a curved spacetime. It is shown that it exactly coincides with the semi-quantitative Hamiltonian, used in our previous papers. We extend the obtained Hamiltonian to the case of a spacecraft, containing a macroscopic ensemble of the atoms and moving with a constant velocity in the Earth's gravitational field. On this basis, we discuss some idealized and realistic experiments on the Earth's orbit. If such (realistic) experiment is done, it will be the first direct observation of quantum effects in the General Relativity. 
Andrei G. Lebed
gr-qc