The Flow Equation Approach to Many-Particle Systems

Over the past decade, the flow equationmethod has developed into a new versatile theoretical approach to quantum many-body physics. Its basic concept was conceived independently by Wegner [1] and by Glazek and Wilson [2, 3]: the derivation of a unitary flow that makes a many-particle Hamiltonian increasingly energy-diagonal. This concept can be seen as a generalization of the conventional scaling approaches in many-body physics, where some ultra-violet energy scale is lowered down to the ex...