Real-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems

TL;DR

This paper discusses how real-space grid methods, exemplified by the Octopus code, enable flexible, efficient, and parallelizable simulations of electronic systems, fostering new approaches in physical modeling and response calculations.

Contribution

It demonstrates the advantages of real-space grid methods and the Octopus code in developing innovative simulation techniques for electronic systems.

Findings

Facilitated new response property calculations

Enabled modeling of photoemission processes

Supported exact Schrödinger equation solutions for low-dimensional systems

Abstract

Real-space grids are a powerful alternative for the simulation of electronic systems. One of the main advantages of the approach is the flexibility and simplicity of working directly in real space where the different fields are discretized on a grid, combined with competitive numerical performance and great potential for parallelization. These properties constitute a great advantage at the time of implementing and testing new physical models. Based on our experience with the Octopus code, in this article we discuss how the real-space approach has allowed for the recent development of new ideas for the simulation of electronic systems. Among these applications are approaches to calculate response properties, modeling of photoemission, optimal control of quantum systems, simulation of plasmonic systems, and the exact solution of the Schr\"odinger equation for low-dimensionality systems.