(545b) Accelerating Molecular Dynamics with Field-Theoretic Simulations

Particle-based simulations like molecular dynamics are ubiquitous throughout academia and industry, yet these methods suffer from several well-known limitations. One limitation is that particle-based simulations struggle to reach equilibrium when a system contains a broad spectrum of timescales, such as in polymeric materials, which often necessitates excessively long simulation times. Another limitation is that the free energy is not directly accessible in a particle-based simulation and must be computed using enhanced sampling methods. In this talk, I describe a new method that address both of these limitations. The basis for our approach is a new type of ``multi-representation'' simulation where particle and field-theoretic simulations are linked together into a unified framework. Our approach involves the construction of formally equivalent particle and field-theoretic models that are simulated subject to the constraint that their spatial density profiles are equal. This constraint provides the ability to rapidly map between particle and field-theoretic representations so that simulations can be performed in the particle/field representation where calculations are most efficient. Our approach can leverage the superior numerical properties of field-theoretic simulations to rapidly relax the largest length scales within a system and to calculate the free energy, yet can backmap into a particle-based representation when molecular configurations and dynamics are desired. Furthermore, by leveraging the formal equivalence between particle and field-based simulations, these calculations can be placed on a rigorous theoretical foundation that can be constructed without approximation. Our method is illustrated using both linear diblock copolymers and intrinsically-disordered proteins. In both cases, our method can provide direct access to the free energy, rapid equilibration, molecular configurations and dynamics.