M. Loss, T. Miyao and H. Spohn
Lowest energy states in nonrelativistic QED: atoms and ions in motion
(112K, latex 2e)

ABSTRACT.  Within the framework of nonrelativisitic quantum electrodynamics we consider a single 
 nucleus and $N$ electrons coupled to the radiation field. Since the total 
 momentum $P$ is conserved, the Hamiltonian $H$ admits a fiber 
 decomposition with respect to $P$ with fiber Hamiltonian $H(P)$. A stable atom, 
 resp. ion, means that the fiber Hamiltonian $H(P)$ has an 
 eigenvalue at the bottom of its spectrum. We establish the existence of 
 a ground state for $H(P)$ under (i) an explicit bound on $P$, 
(ii) a binding condition, and (iii) an energy inequality. The 
 binding condition is proven to hold for a heavy nucleus and the 
 energy inequality for spinless electrons.