Ultrafast ab Initio Quantum Chemistry Using Matrix Product States

Area of Science:

• Quantum Chemistry
• Molecular Dynamics
• Computational Physics

Background:

• Ultrafast dynamics in chemical systems are crucial for understanding molecular processes.
• Describing these quantum systems is computationally challenging.
• Matrix product states (MPS) have emerged as a powerful tool for correlated quantum systems.

Purpose of the Study:

• To advance the MPS approach for studying ultrafast electron dynamics in quantum chemical systems.
• To efficiently solve the time-dependent Schrödinger equation for molecular systems.

Main Methods:

• Combining time evolution schemes (Runge-Kutta, Krylov space) with MPS.
• Solving the time-dependent Schrödinger equation.
• Performing full configurational interaction (CI) level calculations for benchmarking.

Main Results:

• The MPS approach enables efficient simulation of electron dynamics at the full CI level for several femtoseconds.
• Benchmarks on hydrogen chains and water molecules validate the MPS method.
• Simulations of charge migration in iodoacetylene show excellent agreement with experimental data.

Conclusions:

• The developed MPS method is highly effective for simulating ultrafast electron dynamics in molecules.
• The approach provides accurate insights into quantum chemical processes.
• This work validates the MPS approach against experimental observations for charge migration.