Ergodic nonergodic transition in tapped granular systems; The role of persistent contacts

Static granular packs have been studied in the last three decades in the frame of a modi ed equilibrium statistical mechanics that assumes ergodicity as a basic postulate. The canonical example on which this framework is tested consists in the series of static con gurations visited by a granular col...

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Detalhes bibliográficos
Autores: Gago, Paula, Maza, Diego, Pugnaloni, Luis
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2016
País:Argentina
Recursos:Universidad Tecnológica Nacional
Repositorio:Repositorio Institucional Abierto (UTN)
Idioma:inglés
OAI Identifier:oai:ria.utn.edu.ar:20.500.12272/2792
Acesso em linha:http://hdl.handle.net/20.500.12272/2792
Access Level:acceso abierto
Palavra-chave:Ergodicity breaking; Tapped Granular Packs
Descrição
Resumo:Static granular packs have been studied in the last three decades in the frame of a modi ed equilibrium statistical mechanics that assumes ergodicity as a basic postulate. The canonical example on which this framework is tested consists in the series of static con gurations visited by a granular column subjected to taps. By analyzing the response of a realistic model of grains, we demonstrate that volume and stress variables visit di erent regions of the phase space at low tap intensities in di erent realizations of the experiment. We show that the tap intensity beyond which sampling by tapping becomes ergodic coincides with the forcing necessary to break all particle{particle contacts during each tap. These results imply that the well-known \reversible" branch of tapped granular columns is only valid at relatively high tap intensities.

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