title: Depletion forces on circular and elliptical obstacles induced by active matter.
abstract: Depletion forces exerted by self-propelled particles on circular and elliptical passive objects are studied using numerical simulations. We show that a bath of active particles can induce repulsive and attractive forces which are sensitive to the shape and orientation of the passive objects (either horizontal or vertical ellipses). The resultant force on the passive objects due to the active particles is studied as a function of the shape and orientation of the passive objects, magnitude of the angular noise, and distance between the passive objects. By increasing the distance between obstacles the magnitude of the repulsive depletion force increases, as long as such a distance is less than one active particle diameter. For longer distances, the magnitude of the force always decreases with increasing distance. We also found that attractive forces may arise for vertical ellipses at high enough area fraction.
authors.affiliation: Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Campus dos Palmares, 62785-000 Acarape, Ceará, Brazil.|Universidade Federal do Ceará, Departamento de Física Caixa Postal 6030, 60455-760 Fortaleza, Ceará, Brazil.
authors.forename: L R
authors.initials: LR
authors.lastname: Leite
authors.affiliation: Universidade Federal do Ceará, Departamento de Física Caixa Postal 6030, 60455-760 Fortaleza, Ceará, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Lucena
authors.affiliation: Universidade Federal do Pará, Faculdade de Física, ICEN, Av. Augusto Correia, 1, Guamá, 66075-110, Belém, Pará, Brazil.
authors.forename: F Q
authors.initials: FQ
authors.lastname: Potiguar
authors.affiliation: Universidade Federal do Ceará, Departamento de Física Caixa Postal 6030, 60455-760 Fortaleza, Ceará, Brazil.
authors.forename: W P
authors.initials: WP
authors.lastname: Ferreira