Wigner time delays and Goos-H\"{a}nchen shifts of 2D quantum vortices scattered by potential barriers

TL;DR

This paper investigates how 2D quantum vortices affect Wigner time delays and Goos-H"{a}nchen shifts during scattering by potential barriers, revealing significant modifications and resonant enhancements due to vortex presence.

Contribution

It derives analytical formulas for vortex-induced time delays and lateral shifts, extending understanding of wavepacket scattering beyond Gaussian profiles.

Findings

Vortices cause non-zero time delays and lateral shifts even with real scattering coefficients.

Analytical expressions for vortex-induced delays and shifts are validated numerically.

Resonant enhancements occur near critical angles and transmission resonances.

Abstract

We consider reflection and transmission of 2D quantum wavepackets with phase vortices (also known in optics as spatiotemporal vortex pulses) at potential step-like, delta-function, and rectangular barriers. The presence of a vortex significantly modifies the Wigner time delays and Goos-H\"{a}nchen shifts, previously studied for Gaussian-like wavepackets. In particular, the scattered wavepackets undergo non-zero time delays and lateral shifts even for purely real scattering coefficients, when the standard Wigner and Artmann formulae vanish. We derive analytical expressions for the vortex-induced times delays and spatial shifts of 2D vortices and verify these with numerical calculations of the Schr\"{o}dinger equation. The time delays and shifts are resonantly enhanced in the vicinity of the critical-angle incidence for a step-like potential and near transmission resonances for a rectangular barrier.