Fumio Hiroshima, Herbert Spohn
Enhanced binding through coupling to a quantum field
(134K, .dvi)
ABSTRACT. We consider an electron coupled to the quantized
radiation field in the dipole approximation.
Even if the Hamiltonian has no ground state at zero coupling,
$\alpha=0$, the interaction with the quantized radiation field may induce
binding. Under suitable assumptions on the external potential,
we prove that
there exists a critical constant
$\alpha_c\geq0$ such that the Hamiltonian
has a unique ground state for {\it arbitrary} $|\alpha|>\alpha_c$.