Abstract : We study the fluctuations of a Brownian micro particle trapped with optical tweezers in a gelatin solution undergoing a fast local temperature quench below the sol-gel transition. Contrary to what was previously reported, we observe no anomalous fluctuations in the particle's position that could be interpreted in terms of an effective temperature. A careful analysis with ensemble averages shows only equilibrium-like properties for the fluctuations, even though the system is clearly aging. We also provide a detailed discussion on possible artifacts that could have been interpreted as an effective temperature, such as the presence of a drift or a mixing in time and ensemble averages in data analysis. These considerations are of general interest when dealing with non-ergodic or non-stationary systems.
https://hal-ens-lyon.archives-ouvertes.fr/ensl-01192667
Contributeur : Sergio Ciliberto
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Soumis le : jeudi 3 septembre 2015 - 11:41:36
Dernière modification le : jeudi 19 avril 2018 - 14:54:04
Document(s) archivé(s) le : vendredi 4 décembre 2015 - 11:01:38
