Role of PT-symmetry in understanding Hartman effect

Abstract

We calculate the tunneling time from a layered non-Hermitian system to examine the effect of PT-symmetry over tunneling time. We explicitly find that for system respecting PT-symmetry, the tunneling time saturates with the thickness of the PT-symmetric barrier and thus shows the existence of Hartman effect. For non-PT-symmetric case, the tunneling time depends upon the thickness of the barrier and Hartman effect is lost. We further consider the limiting case in which the non-Hermitian system reduces to the real barrier to show that the Hartman effect from a real barrier is due to PT-symmetry (of the corresponding non-Hermitian system).