TwoBody.jl

TwoBody.jl is a Julia package for solving quantum-mechanical two-body problems. It provides a flexible framework for constructing two-body Hamiltonians and solving the corresponding Schrödinger equation using a variety of numerical methods. It covers approaches ranging from basis-set and grid methods to tensor-network, stochastic, and neural-network methods. Beyond serving as a proof of concept for FewBody.jl, TwoBody.jl is designed to support practical, cross-scale calculations of quantum two-body systems, from hadrons to molecules.

Quick Start

Run the following command in the Julia REPL or a notebook:

import Pkg; Pkg.add("TwoBody")

After installation, load the package and verify it works:

using TwoBody

H = Hamiltonian(
  Kinetic(hbar = 1, m = 1),
  Coulomb(coefficient = -1),
)

BS = BasisSet(
  SimpleGaussianBasis(13.00773),
  SimpleGaussianBasis(1.962079),
  SimpleGaussianBasis(0.444529),
  SimpleGaussianBasis(0.1219492),
)

solve(H, BS)

QTT and variational-neural-network solvers are optional. Load TensorTrainNumerics.jl to activate QTT support, or load Lux.jl, Optimisers.jl, and Zygote.jl to activate VNN support. These packages are not installed with the TwoBody.jl core.

Documentation

• Home: https://juliafewbody.github.io/TwoBody.jl
• User Guide:
  • Hamiltonian
  • Database
  • Rayleigh-Ritz Method
  • Gaussian Expansion Method
  • Free Complement Method
  • Finite Difference Method
  • Quantics Tensor Train
  • Variational Monte Carlo
  • Variational Neural Network
• Developer Guide: https://juliafewbody.github.io/TwoBody.jl/dev/developer
• API Reference: https://juliafewbody.github.io/TwoBody.jl/dev/api