Hyperforce correlations in ionic soft matter

Developing a comprehensive microscopic understanding of electrolytes is relevant for a wide range of physical, chemical and biological problems, including battery technology, adsorption of pollutants in soils and the topical area of iontronics, where ions are used for signalling.

Characteristic electrolytic behaviour arises from the response of both ions and solvent molecules to the presence of external electrical fields.

Fundamental physical description can be based on analysing the equilibrium and dynamical fluctuations that occur in a given system.

Relevant fluctuating observables include the particle concentration, the charge, and the electrical current, all of which directly relate to experimentally accessible observables.

The concept of forces, despite being fundamental for physical model building, has received far less attention in statistical mechanics.

Here we intend to introduce a systematic correlation framework based on the forces and hyperforces, which correlate forces with further physical observables, in ionic systems.

Hyperion combines analytical theory with simulation work and it comprises three main tasks: (i) We will first develop and validate the static and dynamic force and hyperforce correlations in bulk, thereby investigating how these relate to number and charge fluctuations. (ii) We will study the influence of external confinement on the electrical fluctuations measured in finite observation volumes as is relevant for transport through channels and nanopores. (iii) We will consider the nonequilibrium correlations that occur during transport induced either by shear flow or by an external electric field with the aim to rationalize the emerging electrophoretic phenomena and the nonequilibrium ion kinetics.

As understanding the electrolyte sheds light on the kinetics of individual ions, Hyperion aims to provide a new point of view for ionic structure and the associated nonequilibrium transport in complex environments.