Calculation of cyclotron resonance linewidths in Ge by using a many-body state-independent projection technique

We present a new many-body projection technique in which the projectors are state-independent. Utilizing the method, we express the conductivity tenso r for a system of electrons in the linear response approximation. The formu la obtained is shown to be simpler and to require a smaller amount of calcu lation for a numerical solution than the one that we used previously with s tate-dependent projectors. The cyclotron resonance linewidth in Ge obtained by using the new technique is also in better agreement with the experiment al data than the previous one.