The general and explicit relation between the phase time and the dwell time
for quantum tunneling or scattering is investigated. Considering a symmetrical
collision of two identical wave packets with an one-dimensional barrier, here
we demonstrate that these two distinct transit time definitions give connected
results where, however, the phase time (group delay) accurately describes the
exact position of the scattered particles. The analytical difficulties that
arise when the stationary phase method is employed for obtaining phase
(traversal) times are all overcome. Multiple wave packet decomposition allows
us to recover the exact position of the reflected and transmitted waves in
terms of the phase time, which, in addition to the exact relation between the
phase time and the dwell time, leads to right interpretation for both of them.Comment: 11 pages, 2 figure