Störungstheoretische Berechnung der Selbstenergie und der Masse des Polarons
Tóm tắt
The perturbation theoretical results for the self-energy and the mass of the polaron are given in 4-th order. Even for a coupling strength usually assumed in NaCl (g2=6) the deviations from the values found inFeynman's variational approach are negligible. A remark concerning the approximation character ofFeynman's method is made from the comparison of the expressions for the self-energy.