Flow Equations and Normal Ordering
arXiv:cond-mat/0509801 · doi:10.1088/0305-4470/39/6/001
Abstract
In this paper we consider flow-equations where we allow a normal ordering which is adjusted to the one-particle energy of the Hamiltonian. We show that this flow converges nearly always to the stable phase. Starting out from the symmetric Hamiltonian and symmetry-broken normal ordering nearly always yields symmetry breaking below the critical temperature.
7 pages