Simple Quantum Dynamics with Thermalization.

Area of Science:

• Quantum dynamics
• Computational chemistry
• Theoretical physics

Background:

• Accurate quantum dynamics simulations are crucial for understanding molecular processes.
• Traditional methods like surface-hopping can be computationally expensive.
• Developing efficient yet accurate methods is an ongoing challenge.

Purpose of the Study:

• Introduce two novel, simplified quantum dynamics methods.
• Evaluate their accuracy and computational efficiency compared to established approaches.
• Assess their applicability to systems with complex bath dynamics.

Main Methods:

• A surface-hopping method utilizing the equipartition theorem for hop criteria.
• A second method based on rescaling non-adiabatic coupling.
• Comparison with the Hierarchical Equations Of Motion (HEOM) approach.

Main Results:

• Both methods approximate quantum dynamics towards thermal equilibrium effectively.
• The first method avoids direct system-to-bath feedback, suitable for pre-calculated trajectories.
• The second method, while neglecting bath relaxation, is computationally tractable.

Conclusions:

• The proposed methods offer a computationally efficient alternative to conventional surface-hopping.
• They are well-suited for simulating quantum dynamics in complex bath scenarios with moderate system-bath coupling.
• These methods provide valuable tools for exploring quantum phenomena in challenging systems.