How to correct Ehrenfest nonadiabatic dynamics in open quantum systems: Ehrenfest plus random force (E + σ) dynamics

Area of Science:

• Quantum mechanics
• Computational chemistry
• Theoretical physics

Background:

• Nonadiabatic dynamics in open quantum systems present a challenge in balancing accuracy and computational cost.
• Traditional Ehrenfest dynamics (ED) is efficient but often lacks accuracy for complex systems.

Purpose of the Study:

• To improve the accuracy of Ehrenfest dynamics for simulating nonadiabatic dynamics in open quantum systems.
• To introduce a computationally efficient method that maintains high accuracy.

Main Methods:

• Developed an enhanced Ehrenfest dynamics (E + σ) method by incorporating random forces.
• Considered both Markovian and non-Markovian scenarios for random force construction.
• Ensured the dynamics satisfy detailed balance in both scenarios.

Main Results:

• The E + σ method demonstrates improved accuracy compared to traditional ED.
• Validated the reliability of E + σ against established methods like electronic friction and surface hopping.
• The enhanced method retains the computational efficiency of ED with minimal overhead.

Conclusions:

• The E + σ model offers a reliable and efficient alternative for simulating mixed quantum-classical dynamics.
• This method is particularly suitable for large and complex open quantum systems.
• Provides a new tool for accurate modeling of quantum dynamics.