The AETHER software

AETHER (Adaptive Expansion of Time-evolving Hilbert-space with Error Reconciliation) is the new generation of multiconfigurational methods for quantum dynamics simulations. It is a high-precision, adaptive computational platform designed to simulate the real-time evolution of strongly correlated quantum many-body systems across domains such as quantum optics, condensed matter, and quantum chemistry.

Building on the MultiConfigurational Time-Dependent Hartree (MCTDH) framework, AETHER dynamically optimizes its basis set during evolution, allowing it to efficiently capture entanglement and correlations that fixed-basis methods struggle with. Its key innovation is the integration of a Local-In-Time Error (LITE) tracking system—based on the McLachlan variational principle—which monitors deviation from exact dynamics in real time. This enables automated, error-controlled adaptation of the active Hilbert space by spawning or pruning orbitals and configurations on the fly, without manual tuning.

Developed in modular C++ with Python interfaces and OpenMP-based parallelism, AETHER is portable, scalable, and ready for integration into high-performance computing environments. GPU offloading is expected to bring orders-of-magnitude speedups, making it ideal for simulating quantum systems beyond the reach of conventional techniques.

With future expansions planned to include neural network parametrizations for even greater compression and scalability, AETHER already provides a powerful and flexible core engine for benchmarking quantum simulators and probing quantum dynamics in realistic, experimentally relevant systems.

Stay tuned for more AETHER updates soon!

The AETHER code is freely available at this repository.

The LITE whitepaper can be found here.