2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/88883We introduce a local concept of speed-up applicable to intermediate stages of a quantum algorithm. We use it to analyse the complementary roles played by quantum parallel computation and quantum measurement in yielding the speed-up. A severe conflict between there being a speed-up and the many worlds interpretation is highlighted.21 pages, RevTex, separate page of figures. With respect to a former work of the same title, the "strong" nondeterministic character of quantum computation is emphasized; a severe conflict between there being a speed-up and the many worlds interpretation is highlightedQuantum Physicstext