Attosecond two-photon interferometry for doubly excited states of helium

TL;DR

This paper demonstrates a method using two-photon interferometry to observe real-time correlation dynamics in doubly excited helium states, enabling detailed mapping of two-electron wave packet evolution.

Contribution

It introduces a novel interferometric approach combined with a semi-analytical model and numerical validation to study two-electron dynamics in helium.

Findings

Interferometric signal accurately reflects two-electron correlation dynamics.

The method allows mapping of the two-electron wave packet onto single-electron spectra.

Validation shows strong agreement between semi-analytical model and numerical solutions.

Abstract

We show that the correlation dynamics in coherently excited doubly excited resonances of helium can be followed in real time by two-photon interferometry. This approach promises to map the evolution of the two-electron wave packet onto experimentally easily accessible non-coincident single electron spectra. We analyze the interferometric signal in terms of a semi-analytical model which is validated by a numerical solution of the time-dependent two-electron Schr\"odinger equation in its full dimensionality.