Rimu.jl: Random integrators for many-body quantum systems

TL;DR

Rimu.jl is a Julia package that provides efficient, high-performance tools for solving many-body quantum problems using stochastic and exact diagonalization methods, including a full configuration interaction quantum Monte Carlo implementation.

Contribution

The paper introduces Rimu.jl, a Julia package with a novel matrix-free, high-performance implementation for many-body quantum computations, including FCIQMC and various Hamiltonians.

Findings

Efficient matrix-free Hamiltonian implementation

Integration of FCIQMC algorithm in Julia

Support for multiple quantum many-body methods

Abstract

Rimu.jl is a Julia package for solving many-body quantum problems. The core of the package is a matrix-free implementation of Hamiltonians and other operators and compact representation of Fock states, which together allow for efficient methods suitable for high-performance computing. Rimu.jl includes a Julia implementation of the full configuration interaction quantum Monte Carlo (FCIQMC) algorithm which is a type of projector QMC algorithm for stochastically solving the time-independent Schr\"odinger equation. It also includes many well-known model Hamiltonians, and an interface for exact diagonalisation based on external eigenvalue solvers. Both the stochastic and exact diagonalisation methods are accessed with a CommonSolve.jl interface. We describe the FCIQMC algorithm and how to obtain estimators of observables as well as the key features of the implementation.