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, α = 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 α* ≥ 0 such that the Hamiltonian has a unique ground state for arbitrary α| > α*. Moreover an explicit lower bound αc of α* is given.
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