quantum mechanics 2 physics

5. Feynman path integrals can be set up in momentum space instead of ordinary space i. e. . (p", t) = / d3p' K(p", t; p', to)(p', to). (a) Show that the propagator can be expressed as K(p", t; p', to) = (p", tip', to) (b) Derive an explicit expression for (p", t(p', to) for the free-particle case