Periodic Reporting for period 1 - EXPMFSG (Search for an experimental test of the mean-field theory of simple glasses)
Reporting period: 2015-07-16 to 2017-07-15
This project has focused the attention in determining the existence of the Gardner transition in realistic systems, both in simulations and experiments. This task represented a great challenge three years ago, mainly because such a transition had never been observed, even though decades of intense investigation of these materials (even in the relevant parameter space).
After testing the theory in hard-sphere systems, the canonical model for granulars or colloids, we explored the existence of a Gardner transition
in temperature in a simple model for molecular glasses in prepared via the vapor deposition procedure. We concluded that, although a Gardner-like threshold is observed at low temperatures, and that this threshold depends on the stability of the original glass, the transition changes its nature when thermal fluctuations are introduced. The threshold is not longer sharp, and it is not related to the apparition of collective excitations but localized ones. In this sense, we find a threshold in temperature but it does not lead to a marginal phase but it is related to localized defects in the sample . Still, many of the anomalies remain visible.
The protocol followed in Refs. [1,2,4] can only be repeated in experiments if spatial resolution is available (like in granular disks), which is not generally the case in most of glassy systems. For this reason, I have also worked in developing new alternative protocols based only on macroscopic observables. During the project, I tested these ideas first in spin glasses [5,6] and I have recently applied to hard-sphere problems, but this work is still ongoing.
 Charbonneau, P., Jin, Y., Parisi, G., Rainone, C., Seoane, B., & Zamponi, F. (2015). Numerical detection of the Gardner transition in a mean-field glass former. Physical Review E, 92(1), 012316.
 Berthier, L., Charbonneau, P., Jin, Y., Parisi, G., Seoane, B., & Zamponi, F. (2016). Growing timescales and lengthscales characterizing vibrations of amorphous solids. Proceedings of the National Academy of Sciences, 201607730.
 Seguin, A., & Dauchot, O. (2016). Experimental Evidence of the Gardner Phase in a Granular Glass. Physical review letters, 117(22), 228001.
 Seoane, B., Reid, D. R., de Pablo, J. J., & Zamponi, F. (2017). Low-temperature anomalies of a vapor deposited glass. arXiv preprint arXiv:1709.04930.
 Baity-Jesi, M., Calore, E., Cruz, A., Fernandez, L. A., Gil-Narvión, J. M., Gordillo-Guerrero, A., ... & Monforte-Garcia, J. (2017). A statics-dynamics equivalence through the fluctuation–dissipation ratio provides a window into the spin-glass phase from nonequilibrium measurements. Proceedings of the National Academy of Sciences, 201621242.
 Baity-Jesi, M., Calore, E., Cruz, A., Fernandez, L. A., Gil-Narvion, J. M., Gordillo-Guerrero, A., ... & Monforte-Garcia, J. (2017). Matching microscopic and macroscopic responses in glasses. Physical Review Letters, 118(15), 157202.