Access to Klein Tunneling via Space-Time Modulation
arXiv:2510.21154 · doi:10.1016/j.aop.2026.170686
Abstract
We show that space-time modulation of electromagnetic potentials enables Klein tunneling far below the static threshold. The derived kinematics reveal oblique transitions that can connect opposite-energy continua without requiring their overlap, yielding a velocity-tunable Klein gap where transmission vanishes within a finite velocity window and reemerges beyond. The associated reduction in energy thresholds -- by up to four orders of magnitude -- suggests the potential for experimental realization using flying-focus fronts and relativistic electron beams.
Main text: 13 pages, 3 figures. Supplementary material: 14 pages, 2 figures