Relativistic tunneling times for Gaussian wave packets

Zharko Tasev, Gjorgji Ivanovski

Sang Pyo Kim, Kyoung Kon Kim

M. Alkhateeb, X. Gutiérrez de la Cal, M. Ll. Pons +2 more

Recent results on electron tunneling across a potential barrier, inferred from observations or obtained from theoretical models, have suggested superluminal or instantaneous barrier traversal times. In this work we investigate relativistic wave-packet dynamics for an electron tunneling through a potential barrier employing space-time resolved solutions to relativistic quantum field theory (QFT) equations. We prove by linking the QFT property of microcausality to the wave-packet behavior that the tunneling dynamics is fully causal, precluding instantaneous or superluminal effects. We illustrate these results by performing numerical computations for an electron tunneling through a potential barrier for standard tunneling as well for Klein tunneling. In all cases (Klein tunneling or regular tunneling across a standard or a supercritical potential) the transmitted wave packet remains in the causal envelope of the propagator, even when its average position lies ahead of the average position of the corresponding freely propagated wave packet.

Yong-Peng Zhang, Sheng-Chang Li

Abstract Tunneling time as an important quantity to characterize tunneling process has not been well defined yet in quantum mechanics. In this paper, we adopt the definition of tunneling time given in [S.-C. Li, New J. Phys. 24, 083033 (2022)] to investigate the time spent by a macroscopic quantum wave packet passing through a Gaussian barrier. We show a general scenario of tunneling times in different energy regimes and find that it has a good agreement with the scenario for a rectangular barrier, which verifies the validity of the above definition of tunneling time for the Gaussian barrier. The influence of both incident energy of wave packet and barrier parameters on tunneling time is discussed thoroughly. The connection between tunneling time and tunneling probability for the Gaussian barrier is established as well. In particular, we use the product of the variances of position and momentum to quantify the deformation of wave packet caused by tunneling process and demonstrate that different behaviors of the variances strongly support our oft-emphasized division of energy regimes.

Jose Tadeu Lunardi, Luiz A. Manzoni, Andrew T. Nystrom +1 more

Dai-Yu Xu, Towe Wang, Xun Xue