Systematic approach to define and classify quantum transmission and reflection times

A systematic procedure to define and/or classify local transmission and reflection times for the passage of a quantum particle through a static potential barrier is described. Previously defined times and new quantities arise as particular cases of the general formalism. Generalizations for multidimensional and multichannel scattering systems are presented. The one-dimensional results are applied in detail to the rectangular potential. Other nonlocal approaches based on the current density are also examined, and the ‘‘Hartman effect’’ is quantitatively characterized for wave packets.