Jones: FYI: your intuitive ruminations about the a.m.u and nuclear masses not being all that 'constant' just might prove insightful! In his latest paper, Hagelstein mentions that excited nuclei have differing masses. The problem he has encountered is that traditional models for condensed matter (which have been quite successful so far) have failed to provide the necessary coupling between nuclear and phononic (lattice) energy transfer. He has come up with a new approach which he thinks has merit. Here are two quotes from that paper to provide some understanding.
"The intuitive picture that has emerged over the past few years of thinking about the problem is that the different excited states of the nucleus have different masses, and under appropriate conditions it may be possible for the nucleus to notice the mass differences of the different configurations. This could provide the physical basis for phonon exchange in association with configuration mixing." "The resulting model can then be used directly to develop a new Hamiltonian for nuclei in a lattice that includes the coupling consistent with a many-particle Dirac formulation. Interestingly, the model that results seems to include a relativistic effect which provides a *direct coupling between the lattice motion and excitations in the nucleus*." Keep on Ruminatin'. J -Mark
