Emergence of dissipation and hysteresis from interactions among reversible, nondissipative units: The case of fluid-fluid interfaces

Fluid-fluid displacement is often irreversible---exhibiting hysteresis where reversal of the driving force (e.g. external pressure) does not reverse the fluids' configuration. This irreversibility is linked to energy dissipation, a key to efficient design of engineering operations such as subsurface cleanup or energy storage. Here, we analyze (analytically, numerically, and experimentally) a novel model system that exposes a striking phenomenon: emergence of hysteresis and dissipation in a system made of individually ``reversible'' (non-hysteretic) entities, due to their spatial interactions mediated by interfacial tension.