Ultrafast laser-driven quantum dynamics in positronium chloride

TL;DR

This study computationally investigates the ultrafast laser-driven quantum dynamics of positronium and its compounds PsH and PsCl, revealing differences in ionization behavior and proposing experimental detection methods for PsCl formation.

Contribution

It introduces a detailed multicomponent time-dependent Hartree-Fock approach with a pseudospectral method to accurately simulate positronium compounds under laser fields, highlighting new dynamical insights.

Findings

Positron delays electron ionization in PsH.

Slight enhancement of electron ionization in PsCl.

Positron response is faster than electrons in both cases.

Abstract

We present a computational study of the laser-driven quantum dynamics of positronium (Ps), PsH, and PsCl at the time-dependent Hartree-Fock level of theory. To eliminate finite-basis effects and to properly capture continuum dynamics, we use a spherical polar pseudospectral representation. The multicomponent theory and its implementation are described in detail. We find that while the presence of the positron delays electron ionization in PsH, a slight enhancement of electron ionization is observed in PsCl. In both cases, the positronic response is faster than that of the electrons. We propose that the formation of PsCl may be directly observed through photopositron spectra in the multiphoton regime, where PsCl peaks are expected at roughly twice the energy of Ps peaks, making PsCl clearly distuinguishable from Ps. In the tunelling regime, however, photopositron rescattering peaks may only be distuinguishable if the amount of Ps is sufficiently low.