A method for estimating the interactions in dissipative particle dynamics from particle trajectories

Area of Science:

• Computational physics
• Statistical mechanics
• Soft matter physics

Background:

• Dissipative Particle Dynamics (DPD) is a coarse-grained simulation method.
• Determining accurate interaction parameters in DPD is crucial for reliable simulations.
• Existing methods may struggle with complex systems or limited timescale separation.

Purpose of the Study:

• To develop a novel method for deriving the functional form of stochastic and dissipative interactions in DPD models.
• To reconstruct all forces within a coarse-grained DPD model from projected phase space trajectories.
• To provide a robust approach applicable to systems with finite timescale separation.

Main Methods:

• Utilizing the Mori-Zwanzig projection operator method to derive a consistency equation for stochastic interactions.
• Solving the consistency equation via an iterative bootstrapping procedure.
• Combining with standard techniques for estimating conservative interactions.

Main Results:

• Successfully reconstructed all forces in a DPD model by analyzing its phase space trajectory.
• Demonstrated the method's capability to determine the functional form of DPD interactions.
• Validated the approach for systems exhibiting clear timescale separation.

Conclusions:

• The developed method enables the accurate reconstruction of DPD model forces from simulation data.
• This technique enhances the predictive power of coarse-grained simulations.
• The approach offers a pathway for more reliable modeling of complex physical systems.