Revivals, collapses and magnetic-pulse generation in quantum rings

TL;DR

This paper presents a microscopic theory of quantum revivals and collapses in mesoscopic rings driven by electromagnetic pulses, enabling ultrafast magnetic field control and advancing studies of spin dynamics.

Contribution

It introduces a novel microscopic approach to analyze quantum revivals and collapses in quantum rings, and demonstrates their application in ultrafast magnetic switching.

Findings

Quantum revivals and collapses can be controlled with short electromagnetic pulses.

Collapsed states enable sub-picosecond current switching.

Generated pulsed magnetic fields have tunable time structure.

Abstract

Using a microscopic theory based on the density matrix formalism we investigate quantum revivals and collapses of the charge polarization and charge current dynamics in mesoscopic rings driven by short asymmetric electromagnetic pulses. The collapsed state is utilized for sub-picosecond switching of the current and associated magnetization, enabling thus the generation of pulsed magnetic fields with a tunable time structure and shape asymmetry which provides a new tool to study ultrafast spin-dynamics and ratchet-based effects.