Unified approach to time-resolved x-ray and electron diffraction imaging

TL;DR

This paper introduces a unified quantum-field-based framework for time-resolved x-ray and electron diffraction imaging, enabling consistent analysis and simulation of ultrafast quantum dynamics in matter.

Contribution

It presents a novel formalism that unifies TR-XRD and TR-UED descriptions, allowing systematic comparison and inclusion of additional physical effects.

Findings

The formalism clarifies the relationship between TR-XRD and TR-UED.

Simulations of laser-driven electron dynamics in graphene demonstrate the approach's capabilities.

The method can incorporate relativistic charge-current effects.

Abstract

Time-resolved x-ray diffraction (TR-XRD) and ultrafast electron diffraction (TR-UED) are emerging tools for probing ultrafast quantum dynamics. From a theoretical perspective, they are commonly described within different frameworks and modeled using distinct approximations. Here, we present a unified quantum-field-based description of ultrafast diffraction imaging that permits consistent consideration of TR-XRD and TR-UED within a common theoretical formalism. Our approach elucidates the correspondence between TR-XRD and TR-UED and allows their similarities and differences to be systematically disentangled. The developed formalism is sufficiently general to consistently and straightforwardly incorporate additional physical effects of interest, such as relativistic charge-current and current-current couplings. We apply our approach to simulate diffraction measurements of laser-driven electron dynamics in graphene, demonstrating the unique capabilities of diffraction imaging to unravel intricate quantum processes in matter.