Quantum Interference in Two-Atom Resonant X-ray Scattering of an Intense Attosecond Pulse

TL;DR

This paper presents a theoretical study of quantum interference effects in resonant x-ray scattering from two neon ions driven by intense attosecond pulses, revealing conditions for optimal interference visibility.

Contribution

It introduces a non-relativistic QED-based model including Rabi oscillations, ionization, and Auger decay to analyze interference in resonant x-ray scattering.

Findings

Resonant scattering yield surpasses non-resonant yield.

Angular dependence resembles a two-atom structure factor.

Interference fringe visibility depends on pulse area and initial state.

Abstract

We theoretically investigate resonant x-ray scattering from two non-interacting Ne+ ions driven by an intense attosecond pulse using a non-relativistic, QED-based time-dependent framework. Our model includes Rabi oscillations, photoionization, Auger decay, and quantum interference among elastic scattering and resonance fluorescence pathways. We analyze how the total scattering signal depends on pulse intensity, atomic configuration, and initial electronic state. We find that the total resonant scattering yield exceeds its non-resonant counterpart; the angular dependence of the signal qualitatively resembles a two-atom structure factor; and the visibility of interference fringes is sensitive to pulse area and the initial electronic state. Only a subset of final states reached via resonance fluorescence exhibits interference, determined by the indistinguishability of photon emission pathways. Fringe visibility is maximized in the linear scattering regime, where ionization is minimal and resonance fluorescence pathways can be largely indistinguishable. These results highlight optimal conditions for applying ultrafast resonant x-ray scattering to single-particle imaging.