Electron-Positron Attosecond Dynamics in exotic systems: Probing correlated matter-antimatter dynamics in real-time – EPAD

The project EPAD aims to provide a theoretical framework to investigate positron-electron dynamics in atoms by means of recent experimental spectroscopy methods developed in attoscience. The positron is the anti-particle of an electron, identical to this latter except for carrying a positive charge. This positive charge makes it possible for a positron to bind to an electron, forming a positronium, or to more complex atomic and molecular structures. It is now established that such hybrid systems, made of matter and antimatter, exist but the experimental investigation remains elusive, especially concerning their time evolution.

Here we suggest, by means of numerical simulations, to theoretically tackle the investigation of electron-positron correlated dynamics during and after excitation with femto- and attosecond light pulses. Being far ahead of experimental realization, we aim to develop predictive models to investigate these hybrid systems. We will numerically solve the time-dependent Schrödinger equation, through wave function-based approaches. Due to the correlation, mediated through electrostatic interaction between charged particles, we expect rich dynamics of the electrons and positrons following the interaction with a light pulse. This includes, for instance, multi-photon ionization, non-radiative decay such as Auger, sequential and non-sequential photon absorption, decay involving both electrons and positrons.

A cornerstone of this project is to provide signatures of these expected dynamics in experimental observables involving ultrafast spectroscopy from attoscience. Indeed, due to the light masses of positrons and electrons, their natural timescale is the attosecond (1 as = 10-18 s). Thus, this proposal will trigger interest from experimental groups that could in the near-future realize such experiments, since individual steps to produce, control, and probe are already available but not assembled together, yet.