Subject: [Depfis] CLUB DE MATERIA CONDENSADA-HOY 13.30

From: "gustavo lozano" <[email-masked]>
Date: Fri, 20 Jun 2008 08:52:06 -0100

HOY A LAS 13.30, AULA SEMINARIO.

Gabriela Pasquini nos contara el paper,

Ageing memory and glassiness of a driven vortex system

Authors: Xu Du, Guohong Li, Eva Y. Andrei, M. Greenblatt, P. Shuk
(Submitted on 6 May 2007)

Journal reference: 	Nature Physics, 3, 111 (2007)

    Abstract: Many systems in nature, glasses, interfaces and
fractures being some examples, cannot equilibrate with their
environment, which gives rise to novel and surprising behaviour such
as memory effects, ageing and nonlinear dynamics. Unlike their
equilibrated counterparts, the dynamics of out-of- equilibrium systems
is generally too complex to be captured by simple macroscopic laws.
Here we investigate a system that straddles the boundary between glass
and crystal: a Bragg glass formed by vortices in a superconductor. We
find that the response to an applied force evolves according to a
stretched exponential, with the exponent reflecting the deviation from
equilibrium. After the force is removed, the system ages with time and
its subsequent response time scales linearly with its age (simple
ageing), meaning that older systems are slower than younger ones. We
show that simple ageing can occur naturally in the presence of
sufficient quenched disorder. Moreover, the hierarchical distribution
of timescales, arising when chunks of loose vortices cannot move
before trapped ones become dislodged, leads to a stretched-exponential
response.

Comments: 	16 pages, 5 figures
Subjects: 	Superconductivity (cond-mat.supr-con)
Journal reference: 	Nature Physics, 3, 111 (2007)
Cite as: 	arXiv:0705.0779v1 [cond-mat.supr-con]

http://xxx.lanl.gov/abs/0705.0779

Todos cordialmente invitados

-- 
Gustavo S Lozano
Depto de Fisica, FCEyN,UBA
PAB I Ciudad Universitaria
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