Field-theoretic simulations beyond <i>δ</i>-interactions: Overcoming the inverse potential problem in auxiliary field models

Modern field-theoretic simulations of complex fluids and polymers are constructed around a particle-to-field transformation that brings an inverse potential u−1 in the model equations. This has restricted application framework to systems characterized by relatively simple pairwise interatomic interactions; for example, excluded volume effects treated through use δ-function interactions. In this study, we first review available nonbonded pair interactions models propose classification. Then, outline problem present alternative approach on basis saddle-point approximation, enabling richer set interaction functions. We test our using as example Morse potential, which finds extensive applications particle-based simulations, calibrate with results from molecular dynamics simulation. The thus obtained is consistent equations, when used stand-alone self-consistent field it produces correct fluid structure starting random initial state density field.