Statistical properties of microphase and bubbly phase-separated active fluids

Area of Science:

• Soft Matter Physics
• Active Matter
• Phase Transitions

Background:

• Active fluids exhibit complex phase behaviors distinct from passive systems.
• The Ostwald process, typically leading to coarsening, can be reversed in active fluids.

Purpose of the Study:

• To investigate the mechanisms of microphase and bubbly phase separation in active fluids.
• To understand the factors governing the size distribution of mesoscopic domains during phase separation.

Main Methods:

• Large-scale simulations of a minimal field theory for active phase separation.
• Development and application of an effective model focusing on domain dynamics.

Main Results:

• Bubbly phase separation results in macroscopic regions of homogeneous and microphase-separated fluids.
• Domain size distribution in microphase-separated fluids is determined by the interplay of Ostwald reversal, coalescence, and nucleation.
• Domain size distributions can be narrowly peaked or broad, eventually reaching a system-size-independent cutoff.

Conclusions:

• The dynamics of Ostwald reversal, coalescence, and nucleation are critical in controlling active fluid phase separation.
• The study provides a framework for understanding domain formation and size selection in active soft matter systems.