Inclusions

 Flexible passive inclusions can spontaneously curve and move due to unbalanced pressures:

 

Quite generally, a passive asymmetric inclusion experiences a force in the active bath,

     

and acts as a pump causing a counter-flow current of active particles:

Conservation of current thenleads to long-range modulations of active particle density

Long-range density/current disturbances lead to long-range interactions between inclusions,

and with confining boundaries

Inclusion can be localized to the boundary, or to center of circular container

Y. Ben Dor, Y. Kafri, M. Kardar, J. Tailleur, Phys. Rev. E 106, 044604 (2022)

Next (Disorder) Outline Pressure Boundary shape Inclusions Disorder Phase separation Boundary disorder Mixtures Summary