title: Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions.
abstract: The "faster-is-slower" (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing.
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Pastor
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Garcimartín
authors.affiliation: Departamento de Ingeniería Mecánica, Facultad Regional La Plata, Universidad Tecnológica Nacional, Av. 60 Esq. 124 S/N, 1900 La Plata, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917 (1033), C. A. de Buenos Aires, Argentina.
authors.forename: Paula A
authors.initials: PA
authors.lastname: Gago
authors.affiliation: Departamento de Ingeniería Mecánica, Facultad Regional La Plata, Universidad Tecnológica Nacional, Av. 60 Esq. 124 S/N, 1900 La Plata, Argentina.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Peralta
authors.affiliation: Departamento de Construcción, Instalaciones y Estructuras, Escuela Técnica Superior de Arquitectura, Universidad de Navarra, E-31080 Pamplona, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Martín-Gómez
authors.affiliation: Departamento de Patología Animal, Facultad de Veterinaria, Universidad de Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Ferrer
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Maza
authors.affiliation: Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917 (1033), C. A. de Buenos Aires, Argentina.|Instituto Tecnológico de Buenos Aires, 25 de Mayo 444, (1002) C. A. de Buenos Aires, Argentina.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Parisi
authors.affiliation: Departamento de Ingeniería Mecánica, Facultad Regional La Plata, Universidad Tecnológica Nacional, Av. 60 Esq. 124 S/N, 1900 La Plata, Argentina.|Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917 (1033), C. A. de Buenos Aires, Argentina.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Pugnaloni
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Navarra, E-31080 Pamplona, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Zuriguel
mesh_terms: D000818:Animals; D017276:Friction; D006801:Humans; D007700:Kinetics; D009038:Motion; D009068:Movement; D012756:Sheep / Q000502:physiology; D014732:Vibration