PathSum: A C++ and Fortran suite of fully quantum mechanical real-time path integral methods for (multi-)system +...

Area of Science:

• Computational Chemistry
• Quantum Dynamics
• Software Development

Background:

• Accurate simulation of quantum dynamics is crucial for understanding molecular and material properties.
• Existing methods often face limitations in scalability and applicability to complex systems.
• Path integral methods offer a powerful framework for quantum dynamics but require efficient implementations.

Purpose of the Study:

• Introduce PathSum, a novel software suite implementing state-of-the-art path integral methods.
• Provide tools for studying the dynamics of single or extended quantum systems coupled to harmonic environments.
• Facilitate research in areas such as quantum spin chains and excitonic molecular aggregates.

Main Methods:

• PathSum includes two modules: one for system-bath problems and another for extended systems.
• The system-bath module features the small matrix path integral (SMatPI) and iterative quasi-adiabatic propagator path integral (i-QuAPI) methods.
• The extended system module offers modular path integral methods for quantum spin chains and molecular aggregates.

Main Results:

• PathSum provides C++ and Fortran implementations of advanced path integral techniques.
• The SMatPI module incorporates QuAPI, blip sum, time evolving matrix product operators, and quantum-classical path integral.
• The software facilitates the study of diverse quantum dynamics regimes and complex systems.

Conclusions:

• PathSum offers a versatile and efficient computational tool for quantum dynamics research.
• The suite's modular design and multiple algorithms cater to a wide range of applications.
• This release empowers researchers to explore complex quantum phenomena with enhanced accuracy and scalability.