Software projects

WavePacket is a program package for numerical simulation of quantum-mechanical wavepacket dynamics of distinguishable particles. It can be used to solve single or coupled time-independent or time-dependent (linear) Schrödinger and Liouville-von Neumann-equations, partly also classical or quantum-classical Liouville equations. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket can be used to simulate modern experiments involving ultrashort light pulses in photo-induced physics or chemistry, including quantum optimal control. Allowing for easy visualization of quantum dynamics 'on the fly', WavePacket is suitable for teaching quantum mechanics as well as for research projects in physics and chemistry, see also the numerous demo examples that can be found on the associated Wiki pages.

• Matlab/Octave version: recommended version 7.2.0 (18-Jan-2024): in a stable/mature state
  A thorough description of this software package can be found in our series of WavePacket publications [75] [78] [82]

• C++/Python version: latest version 0.3.5 (10-Apr-2023): still in an early phase

Available at SourceForge since Sep 03, 2008.

WaveTrain is an open-source software for numerical simulations of chain-like quantum systems with nearest-neighbor (NN) interactions only. (with or without periodic boundary conditions). This Python package is centered around tensor train (TT, or matrix product) representations of quantum-mechanical Hamiltonian operators and (stationary or time-evolving) state vectors. WaveTrain builds on the Python tensor train toolbox scikit_tt, which provides efficient construction methods, storage schemes, as well as solvers for eigenvalue problems and linear differential equations in the TT format.

WaveTrain comprises solvers for time-independent and time-dependent Schrödinger equations employing efficient decompositions to construct low-rank representations. Often, the tensor-train ranks of state vectors are found to depend only marginally on the chain length N, which results in the computational effort growing only slightly more than linearly in N, thus mitigating the curse of dimensionality. Hence, WaveTrain complements the existing WavePacket project at SourceForge which does not offer these advantages but which can be used for general Hamiltonians, i.e., without restriction to chain-like systems.

As a complement to the Python classes for full quantum mechanics, WaveTrain also contains classes for fully classical and mixed quantum-classical (Ehrenfest or mean field) dynamics of bipartite systems comprising "light" and "heavy" particles. Moreover, the graphical capabilities allow visualization ‘on the fly’, with a choice of several different graphical representations based on reduced densities.

Available at GitHub since May 28, 2022. A thorough description of this software package can be found in our WaveTrain publication [88].