# DCA++: A software framework to solve correlated electron problems with modern quantum cluster methods

## TL;DR

DCA++ is an open-source, high-performance software framework that implements advanced quantum cluster algorithms to solve strongly correlated electron problems, scalable across various modern computing architectures.

## Contribution

It introduces a scalable, portable implementation of the dynamical cluster approximation and its extension, with sustainable development practices for quantum many-body simulations.

## Key findings

- Achieves efficient scalability from workstations to supercomputers
- Provides portable performance on CPU-GPU hybrid architectures
- Supports insights into high-temperature superconductivity

## Abstract

We present the first open release of the DCA++ project, a high-performance research software framework to solve quantum many-body problems with cutting edge quantum cluster algorithms. DCA++ implements the dynamical cluster approximation (DCA) and its DCA$^+$ extension with a continuous self-energy. The algorithms capture nonlocal correlations in strongly correlated electron systems, thereby giving insight into high-$T_c$ superconductivity. The code's scalability allows efficient usage of systems at all scales, from workstations to leadership computers. With regard to the increasing heterogeneity of modern computing machines, DCA++ provides portable performance on conventional and emerging new architectures, such as hybrid CPU-GPU, sustaining multiple petaflops on ORNL's Titan and CSCS' Piz Daint supercomputers. Moreover, we show how sustainable and scalable development of the code base has been achieved by adopting standard techniques of the software industry. These include employing a distributed version control system, applying test-driven development and following continuous integration.