Entanglement in Elastic Electron Scattering: Perturbation theory misses fundamental aspects of Bragg scattering

TL;DR

This paper presents a quantum approach to elastic electron scattering, revealing entanglement effects neglected by traditional perturbative models, with implications for material analysis and imaging contrast.

Contribution

It introduces a quantum treatment that accounts for atom-electron entanglement, challenging the conventional static potential approximation in scattering theory.

Findings

Entanglement between electrons and atoms affects coherence.

Decoherence impacts Bragg scattering on nanoparticles.

Conditions for classical scattering theory recovery are identified.

Abstract

Elastic electron scattering is one of the primary means of investigating materials on the atomic scale. It is usually described by modeling the sample as a fixed, static, perturbative potential, thereby completely neglecting the quantum nature of the atoms inside. In this work, we present a quantum treatment of elastic electron scattering. We show that the interaction of the probe beam and the sample results in entanglement between the two systems, which can have far-reaching consequences, particularly on coherence and image contrast. As a timely example, we discuss decoherence in Bragg scattering on nanoparticles. We also investigate under which conditions the conventional scattering theory is recovered.