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Updated: Sep 30, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Real-time evolution of static electron-phonon models in time-dependent electric fields.
Manuel Weber1,2, James K Freericks1
1Department of Physics, Georgetown University, Washington, DC 20057, USA.
We developed an exact Monte Carlo method for simulating electron-phonon dynamics in the adiabatic limit. This approach accurately models charge-density-wave systems under pulsed electric fields, crucial for pump-probe experiments.
Area of Science:
- Condensed Matter Physics
- Quantum Dynamics
- Computational Physics
Background:
- Electron-phonon interactions are fundamental to many condensed matter phenomena.
- Simulating nonequilibrium dynamics in these systems is computationally challenging.
- The adiabatic limit offers a simplified yet relevant regime for study.
Purpose of the Study:
- To develop an exact Monte Carlo method for simulating nonequilibrium electron-phonon dynamics.
- To apply this method to charge-density-wave systems under pulsed electric fields.
- To investigate the response of the Holstein model in one and two dimensions.
Main Methods:
- Exact Monte Carlo simulation in the adiabatic limit (zero phonon frequency).
- Classical sampling of equilibrium phonon distributions.
- Efficient time-dependent evolution of the electronic subsystem in electromagnetic fields.
- Calculation of current, energy, and photoemission spectra.
Main Results:
- The method accurately simulates nonequilibrium dynamics for electron-phonon models.
- Demonstrated utility for charge-density-wave systems in pump-probe scenarios.
- Calculated out-of-equilibrium responses and photoemission spectra for the Holstein model.
- Controlled finite-size effects for system sizes up to 162 sites (1D) and 16x16 lattices (2D).
Conclusions:
- The developed Monte Carlo method provides an exact and efficient tool for studying nonequilibrium electron-phonon dynamics.
- This approach is particularly valuable for understanding phenomena like charge-density waves under external fields.
- The findings offer insights into experimental techniques such as pump-probe spectroscopy.
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