Stack: Fortran, C++14, parallelization with MPI and OpenMP, CUDA.
TurboRVB is a scientific software package written mainly in Fortran (and a bit of C++) for performing highly accurate and efficient simulations of molecules and solid materials from first principles, which means by solving directly the Schrodinger equation describing the quantum system under study. TurboRVB implements quantum Monte Carlo, a set of simulation techniques which can be executed highly efficiently on the largest super computers in the world.
During my PhD, my main contribution was the code for computing the properties of solids (i.e. periodic materials) combined with several efficient parallelization schemes to enable large-scale calculations.
After more than 10 years of development, TurboRVB is now an open-source project which can be found on GitHub. A few years ago, we published a review paper with a detailed description of its features and performance.
More on Quantum Monte Carlo
Quantum Monte Carlo is one of the most promising techniques for simulating molecules and materials which can compute properties with higher accuracy than other methods (in technical terms, QMC is a highly correlated method). In a nutshell, QMC uses classical Monte Carlo techniques for computing a direct solution of the Schrodinger equation which fully describes all the properties of any quantum system. Thanks to the Monte Carlo component, QMC is highly parallelizable and it can run efficiently on the largest supercomputers in the world. Furthermore, thanks to its high accuracy, it can be applied to the study of some of the most complex phenomena in chemistry and materials science such as high-temperature superconductors, hydrogen under high pressure and many more.