Fumio Hiroshima
Nonrelativistic QED at large momentum of photons 
(59K, latex)

ABSTRACT.  An interaction system 
of one spinless electron 
minimally coupled to a quantized radiation field is considered. 
On the Hamiltonian, $\hl$, of this system, 
an ultraviolet cutoff $\Lambda>0$ 
and an infrared cutoff $\lambda>0$ are 
imposed. 
We do {\it not} assume the existence of a ground state 
of the decoupled Hamiltonian. 
It is proven, however, that 
there exists $\Lambda_\ast$ such that 
for all $\Lambda>\Lambda_\ast$, 
 $\hl$ has a unique ground state. 
Furthermore we investigate the asymptotic behavior 
of $g(\Lambda)=\is (\hl)$ 
without external potentials as $\Lambda\rightarrow \infty$.