Nonadiabatic Approach to Spin-Peierls Transitions via Flow Equations
  The validity of the adiabatic approach to spin-Peierls transitions is assessed. An alternative approach is developed which maps the initial magneto-elastic problem to an effective magnetic problem only. Thus the equivalence of magneto-elastic solitons and magnetic spinons is shown. No soft phonon is required for the transition. Temperature dependent couplings are predicted in accordance with the analysis of experimental data. 
Goetz S. Uhrig