Coutinho, FABNogami, Y.Tomio, L.2014-05-202014-05-201999-04-01Physical Review A. College Pk: American Physical Soc, v. 59, n. 4, p. 2624-2630, 1999.1050-2947http://hdl.handle.net/11449/23981Regarding the Pauli principle in quantum field theory and in many-body quantum mechanics, Feynman advocated that Pauli's exclusion principle can be completely ignored in intermediate states of perturbation theory. He observed that all virtual processes (of the same order) that violate the Pauli principle cancel out. Feynman accordingly introduced a prescription, which is to disregard the Pauli principle in all intermediate processes. This ingenious trick is of crucial importance in the Feynman diagram technique. We show, however, an example in which Feynman's prescription fails. This casts doubts on the general validity of Feynman's prescription. [S1050-2947(99)04604-1].2624-2630engArtigo10.1103/PhysRevA.59.2624WOS:000079609100017Acesso abertoWOS000079609100017.pdf