Decoherence in Attosecond Photoionization

TL;DR

This paper investigates how interchannel coupling affects the coherence of hole states in xenon during attosecond photoionization, revealing limits on creating perfectly coherent hole wave packets despite broad spectral bandwidths.

Contribution

It demonstrates that interchannel coupling reduces coherence and entanglement, showing that increasing spectral bandwidth alone cannot produce perfectly coherent hole states.

Findings

Interchannel coupling decreases hole state coherence.

Entanglement between photoelectron and ion is enhanced by interchannel coupling.

Broad spectral bandwidth does not guarantee coherent hole wave packets.

Abstract

The creation of superpositions of hole states via single-photon ionization using attosecond extreme-ultraviolet pulses is studied with the time-dependent configuration interaction singles (TDCIS) method. Specifically, the degree of coherence between hole states in atomic xenon is investigated. We find that interchannel coupling not only affects the hole populations, it also enhances the entanglement between the photoelectron and the remaining ion, thereby reducing the coherence within the ion. As a consequence, even if the spectral bandwidth of the ionizing pulse exceeds the energy splittings among the hole states involved, perfectly coherent hole wave packets cannot be formed. For sufficiently large spectral bandwidth, the coherence can only be increased by increasing the mean photon energy.