Model-Free Measurement of the Pair Potential in Colloidal Fluids Using Optical Microscopy

Adam E Stones, Roel PA Dullens, and Dirk GAL Aarts

Phys. Rev. Lett. 2019 123 098002

We report a straightforward, model-free approach for measuring pair potentials from particle-coordinate data, based on enforcing consistency between the pair distribution function measured separately by the distance-histogram and test-particle insertion routes. We demonstrate the method's accuracy and versatility in simulations of simple fluids, before applying it to an experimental system composed of super-paramagnetic colloidal particles. The method will enable experimental investigations into many-body interactions and allow for effective coarse graining of interactions from simulations.