Читать книгу Foundations of Quantum Field Theory - Klaus D Rothe - Страница 13

From (2.3) one has for a boost in the z-direction, taking the particle from rest to a momentum ,³

where⁴

Since

we may parametrize γ and βγ as follows:

or (2.13) now reads

Note that this is a hermitian matrix! For a boost in an arbitrary direction one can show that the corresponding matrix elements are given by (note that )