CECAM workshop: "Mesoscale modelling of driven disordered materials: From glasses to active matter"

You can apply to participate and find all the relevant information (speakers, abstracts, program,...) on the event website: https://www.cecam.org/workshop-details/1206
Registration for this workshop is formally closed. Please get in touch with the organizers directly if you would like to discuss participation.

DESCRIPTION
Amorphous materials are ubiquitous around us, encompassing for instance colloids, emulsions, foams, granular matter and metallic glasses, as well as confluent biological tissues. These materials are seemingly very different from each other, as the size of their constituent particles ranges from nanometers (e.g. metallic glasses) to millimeters (e.g. grains) with very dissimilar particle interactions. Nevertheless, they exhibit common features under external forces or self-propulsion, showing universal non-equilibrium behaviours such as localised plastic rearrangements, collective or avalanche-type motion, or the emergence of shear bands. These remarkable observations naturally led researchers to search for a unified description of driven amorphous materials, particularly at a mesoscopic scale where microscopic details become irrelevant [1,2].
It is now well established that the mechanical response of amorphous solids under loading proceeds from local and irreversible rearrangements, resetting disorder locally and generating a highly non-trivial mechanical noise [1,2]. These plastic events were first identified by Argon [3] and later on coined as shear transformation zones (STZs) [4]. They play a central role in mechanical and rheological properties, providing us with the key building blocks for various theoretical descriptions, such as STZ theory [4] and elasto-plastic models (EPMs) [2]. The development of these effective descriptions has been tightly related to advances on other non-equilibrium statistical physics phenomena, such as the depinning transition [5,6] and ferromagnets in random fields [7]. Recent advances in stochastic processes, such as random resetting, could provide useful theoretical tools to refine these descriptions [8]. In this context, understanding the nature of the noise and the characterisation of local disorder is becoming one of the forefront of numerous works, particularly for dense active matter [9] where classical equilibrium concepts are challenged.
On the numerical front, spatio-temporal scales accessible by molecular dynamics are limited. Thus atomistic simulations have been complemented by discrete mesoscopic approaches, allowing to reproduce the response of driven amorphous materials while considerably reducing the number of degrees of freedom to be processed [2]. EPMs consider a discrete population of STZs triggered in an elastic medium, and can be seen as a mechanical analogue of an Ising model where local plastic deformation and elastic propagator correspond respectively to spin and interaction between the sites. Many versions of coarse-grained, mesoscopic modellings  with different ingredients have been devised to investigate the collective organisation of STZs, either spatially-resolved [2,10] or effectively mean-field [11], to explore various mechanisms (e.g. avalanches, shear bands [12]) and rheological settings (e.g. stationary, transient regimes, oscillatory protocols [13,14]). Furthermore, recent studies focused on the detailed calibration of these mesoscopic models using microscopic information obtained by molecular simulations [16,17]. This multiscale-modelling approach, mapping from molecular simulations to mesoscopic models, paves the way to construct more realistic modelling, also by applying them to experimental systems such as colloids and granular materials [18,19]. Such mesoscopic modelling is also becoming paramount for dense active matter, by relying on connections with driven yet passive amorphous materials within a unified framework [20].

Reference
[1] D. Rodney, A. Tanguy, D. Vandembroucq, Modelling Simul. Mater. Sci. Eng., 19, 083001 (2011)
[2] A. Nicolas, E. Ferrero, K. Martens, J. Barrat, Rev. Mod. Phys., 90, 045006 (2018)
[3] A. Argon, H. Kuo, Materials Science and Engineering, 39, 101-109 (1979)
[4] M. Falk, J. Langer, Phys. Rev. E, 57, 7192-7205 (1998)
[5] J. Lin, E. Lerner, A. Rosso, M. Wyart, Proc. Natl. Acad. Sci. U.S.A., 111, 14382-14387 (2014)
[6] B. Tyukodi, S. Patinet, S. Roux, D. Vandembroucq, Phys. Rev. E, 93, 063005 (2016)
[7] G. Biroli, C. Cammarota, G. Tarjus, M. Tarzia, Phys. Rev. B, 98, 174206 (2018)
[8] M. Evans, S. Majumdar, G. Schehr, J. Phys. A: Math. Theor., 53, 193001 (2020)
[9] L. Berthier, E. Flenner, G. Szamel, J. Chem. Phys., 150, 200901 (2019)
[10] Ge Zhang, Hongyi Xiao, Entao Yang, Robert J. S. Ivancic, Sean A. Ridout, Robert A. Riggleman, Douglas J. Durian, and Andrea J. Liu,
Phys. Rev. Research, 4, 043026 (2020)
[11] E. Agoritsas, E. Bertin, K. Martens, J. Barrat, Eur. Phys. J. E, 38, 71 (2015)
[12] H. Barlow, J. Cochran, S. Fielding, Phys. Rev. Lett., 125, 168003 (2020)
[13] M. Mungan, S. Sastry, Phys. Rev. Lett., 127, 248002 (2021)
[14] J. Parley, S. Sastry, P. Sollich, Phys. Rev. Lett., 128, 198001 (2022)
[15] H. Borja da Rocha, L. Truskinovsky, Phys. Rev. Lett., 124, 015501 (2020)
[16] D. Fernández Castellanos, S. Roux, S. Patinet, Comptes Rendus. Physique, 22, 135-162 (2021)
[17] C. Liu, S. Dutta, P. Chaudhuri, K. Martens, Phys. Rev. Lett., 126, 138005 (2021)
[18] O. Dauchot, G. Marty, G. Biroli, Phys. Rev. Lett., 95, 265701 (2005)
[19] P. Schall, D. Weitz, F. Spaepen, Science, 318, 1895-1899 (2007)
[20] P. Morse, S. Roy, E. Agoritsas, E. Stanifer, E. Corwin, M. Manning, Proc. Natl. Acad. Sci. U.S.A., 118, (2021)