%0 Journal Article
%T Ground state degeneracy of the Pauli-Fierz Hamiltonian with spin
%A F. Hiroshima
%A H. Spohn
%J Mathematics
%D 2002
%I arXiv
%X We consider an electron, spin 1/2, minimally coupled to the quantized radiation field in the nonrelativistic approximation, a situation defined by the Pauli-Fierz Hamiltonian $H$. There is no external potential and $H$ fibers according to the total momentum $p$. We prove that the ground state subspace of $H$ with a total momentum $p$ is two-fold degenerate provided the charge $e$ and the total momentum $p$ are sufficiently small. We also establish that the total angular momentum of the ground state subspace is $\pm1/2$ and study the case of a confining external potential.
%U http://arxiv.org/abs/math-ph/0205018v1