Langevin equation with colored noise for constant-temperature molecular dynamics simulations

Area of Science:

• Computational physics
• Molecular dynamics simulations

Background:

• Constant-temperature molecular dynamics (MD) simulations are crucial for studying thermodynamic properties.
• Traditional thermostats can introduce artifacts or require extensive tuning.
• Controlling system temperature while preserving dynamics is a key challenge.

Purpose of the Study:

• To present a novel approach for constant-temperature molecular dynamics using a Langevin equation with colored noise.
• To demonstrate the ability to tune system relaxation times for optimized equilibration.
• To show temperature control in Car-Parrinello-like dynamics without perturbing electronic degrees of freedom.

Main Methods:

• Utilizing a Langevin equation with colored (correlated) noise as a thermostat.
• Analyzing the linear response of Hamiltonian systems to this thermostat.
• Tuning frequency-dependent relaxation times of system modes.
• Applying the method to Car-Parrinello-like dynamics.

Main Results:

• The proposed method allows precise prediction and control of system response to the thermostat.
• Relaxation times of different frequency modes can be independently tuned.
• Optimized equilibration times and generation of independent configurations are achieved.
• Temperature control is demonstrated in Car-Parrinello dynamics without compromising electronic-ionic decoupling.

Conclusions:

• The colored noise Langevin thermostat offers an effective way to perform constant-temperature MD.
• Frequency-dependent tuning enables efficient equilibration and configuration sampling.
• The method is compatible with advanced simulation techniques like Car-Parrinello dynamics.