📦 QuantumGaussianDynamics.jl

A Julia package for simulating quantum nuclear dynamics of materials under impulsive radiation, based on the Time-Dependent Self-Consistent Harmonic Approximation (TD-SCHA).

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Features

• Integration of TD-SCHA equations of motion for nuclear quantum dynamics
• Handles electric fields of custom shape and intensity
• Interfaces with ASE and CellConstructor for calculator backends

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Installation

To use this package, you must first install the CellConstructor module from the SSCHA code. Note: For compatibility with CellConstructor, Python 3.10 is required.

conda create -n sscha -c conda-forge python=3.10 gfortran libblas lapack openmpi openmpi-mpicc pip numpy scipy spglib=2.2 setuptools=64 pkgconfig
conda activate sscha
pip install ase 
pip install 'cellconstructor==1.4.1'
pip install 'python-sscha==1.4.1' 

Clone the folder locally

git clone git@github.com:NonequilibriumQuantumGaussianDynamics/QuantumGaussianDynamics.jl.git

and instantiate the package

julia --project=/path/to/QuantumGaussianDynamics

using Pkg
Pkg.instantiate()

This will create a file named Manifest.toml contaning the current state of the environment.

Sometimes the default python used by PyCall is different with respect to the main one on which all the packages are installed. This can be checked with

using PyCall; PyCall.python

if the output is different to that of

which python

then the pkg PyCall should be rebuild as

ENV["PYTHON"] = "[path to the right python]"
import Pkg
Pkg.build("PyCall")

References

Details about the numerical methods can be found at

F. Libbi et al., Atomistic simulations of out-of-equilibrium quantum nuclear dynamics, npj Computational Materials 11, 144 (2025) https://doi.org/10.1038/s41524-025-01588-4

while the thoeretical formulation is conteined in

L. Monacelli et al., Time-dependent self-consistent harmonic approximation: Anharmonic nuclear quantum dynamics and time correlation functions, Physical Review B 103, 104305 (2021) https://journals.aps.org/prb/abstract/10.1103/PhysRevB.103.104305

A. Siciliano et al., Wigner Gaussian dynamics: Simulating the anharmonic and quantum ionic motion, Physical Review B 107, 174307 (2023) https://journals.aps.org/prb/abstract/10.1103/PhysRevB.107.174307