Characterizing Fano Resonances During Recollision

TL;DR

This paper investigates Fano resonances during electron recollision in intense light fields, demonstrating how in situ measurements can isolate multielectron effects and advance time-dependent electronic structure understanding.

Contribution

It introduces a method to unambiguously isolate multielectron dynamics during recollision using in situ measurements, enhancing the understanding of complex quantum systems.

Findings

Multielectron effects significantly alter recollision trajectories.

In situ measurements can isolate and identify Fano resonances.

The approach advances time-dependent ab initio electronic structure theory.

Abstract

When intense light irradiates a quantum system, an ionizing electron recollides with its parent ion within the same light cycle and, during that very brief (few femtosecond) encounter, its kinetic energy sweeps from low to high energy and back. Therefore, recollision offers unprecedented time resolution and it is the foundation on which attosecond science is built. For simple systems, recolliding trajectories are shaped by the strong field acting together with the Coulomb potential and they can be readily calculated and measured. However, for more complex systems, multielectron effects are also important because they dynamically alter the recolliding wave packet trajectories. Here, we theoretically study Fano resonances, one of the most accessible multielectron effects, and we show how multielectron dynamics can be unambiguously isolated when we use in situ measurement. The general class of in situ measurement can provide key information needed for time-dependent ab initio electronic structure theory and will allow us to measure the ultimate time response of matter.