Field theory fo charged fluids and colloids

TL;DR

This paper develops a comprehensive field theory for charged fluids and colloids, extending classical Debye-Hückel theory to include multi-body correlations and higher-order corrections, revealing complex interactions and phase behaviors.

Contribution

It introduces a systematic loop expansion framework for charged systems that captures multi-body effects and predicts novel interactions and phase separation phenomena.

Findings

One-loop level reproduces Debye-Hückel theory.

Higher-loop corrections show attractive colloid interactions.

Deviations from DH theory in phase behavior for strongly charged colloids.

Abstract

A systematic field theory is presented for charged systems. The one-loop level corresponds to the classical Debye-H\"uckel (DH) theory, and exhibits the full hierarchy of multi-body correlations determined by pair-distribution functions given by the screened DH potential. Higher-loop corrections can lead to attractive pair interactions between colloids in asymmetric ionic environments. The free energy follows as a loop-wise expansion in half-integer powers of the density; the resulting two-phase demixing region shows pronounced deviations from DH theory for strongly charged colloids.