The quantum action principle revisited

Abstract

We investigate the basic assumptions leading to Schwinger’s quantum action principle in quantum mechanics. We present this principle in a new way that clarifies some previous developments, for example, the derivation of the fundamental commutators among the canonical variables and the Heisenberg equation for operators. We define operators associated with the classical transformations of the Galilei group, i.e., translations, boosts, and rotations and show their commutators obey the Lie algebra of the Galilei group.PACS Nos.: 83.65.Ca, 11.10.Ef