Exact factorization of the photon-electron-nuclear wavefunction: Formulation and coupled-trajectory dynamics.

Area of Science:

• Quantum mechanics
• Strong light-matter interactions
• Computational chemistry

Background:

• Electron-nuclear dynamics are crucial in many chemical and physical processes.
• Simulating these dynamics accurately, especially under strong light, is computationally challenging.
• Existing methods often struggle with the coupled quantum nature of these systems.

Purpose of the Study:

• To develop and apply a quantum mechanical formalism for coupled electron-nuclear dynamics.
• To investigate nonadiabatic dynamics and spontaneous emission in strong light-matter coupling regimes.
• To assess the performance of the coupled-trajectory mixed quantum-classical (CTMQC) algorithm.

Main Methods:

• Employed the exact-factorization formalism for multi-component wavefunctions.
• Factored the wavefunction into conditional electronic and marginal photon-nuclear amplitudes.
• Applied the coupled-trajectory mixed quantum-classical (CTMQC) algorithm for trajectory-based simulations.
• Treated photonic and nuclear degrees of freedom classically.

Main Results:

• Demonstrated a method for studying coupled photon-electron-nuclear dynamics.
• Identified limitations in current CTMQC approximations.
• CTMQC simulations showed higher prediction quality compared to multi-trajectory Ehrenfest and Tully surface hopping algorithms.

Conclusions:

• The exact-factorization approach combined with CTMQC offers a robust framework for strong light-matter interactions.
• CTMQC provides a more accurate description of electron-nuclear dynamics than alternative trajectory-based methods.
• Further refinement of CTMQC approximations is warranted for complex systems.