https://libjncir.jncasr.ac.in/xmlui/handle/10572/1545 Sat, 04 Apr 2026 05:30:33 GMT 2026-04-04T05:30:33Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2537 Encoding of Memory in Sheared Amorphous Solids Fiocco, Davide; Foffi, Giuseppe; Sastry, Srikanth We show that memory can be encoded in a model amorphous solid subjected to athermal oscillatory shear deformations, and in an analogous spin model with disordered interactions, sharing the feature of a deformable energy landscape. When these systems are subjected to oscillatory shear deformation, they retain memory of the deformation amplitude imposed in the training phase, when the amplitude is below a "localization" threshold. Remarkably, multiple persistent memories can be stored using such an athermal, noise-free, protocol. The possibility of such memory is shown to be linked to the presence of plastic deformations and associated limit cycles traversed by the system, which exhibit avalanche statistics also seen in related contexts. Restricted Access Wed, 01 Jan 2014 00:00:00 GMT https://libjncir.jncasr.ac.in/xmlui/handle/10572/2537 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2535 Aggregation dynamics, structure, and mechanical properties of bigels Di Michele, L.; Fiocco, D.; Varrato, F.; Sastry, Srikanth; Eiser, E.; Foffi, G. Recently we have introduced bigels, inter-penetrating gels made of two different colloidal species. Even if particles with simple short-range isotropic potential are employed, the selective interactions enable the tunability of the self-assembly, leading to the formation of complex structures. In the present paper, we explore the non-equilibrium dynamics and the phenomenology underlying the kinetic arrest under quench and the formation of bigels. We demonstrate that the peculiar bigel kinetics can be described through an arrested spinodal decomposition driven by demixing of the colloidal species. The role played by the presence of a second colloidal species on the phase diagram, as expanded to account for the increased number of parameters, is clarified both via extensive numerical simulations and experiments. We provide details on the realisation of bigels, by means of DNA-coated colloids (DNACCs), and the consequent imaging techniques. Moreover we evidence, by comparison with the usual one-component gel formation, the emergence of controllable timescales in the aggregation of the bigels, whose final stages are also experimentally studied to provide morphological details. Finally, we use numerical models to simulate the bigel response to mechanical strain, highlighting how such a new material can bear significantly higher stress compared to the usual one-component gel. We conclude by discussing possible technological uses and by providing insights on the viable research steps to undertake for more complex and yet tuneable multi-component colloidal systems. Restricted Access Wed, 01 Jan 2014 00:00:00 GMT https://libjncir.jncasr.ac.in/xmlui/handle/10572/2535 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2538 Free volume distribution of nearly jammed hard sphere packings Maiti, Moumita; Sastry, Srikanth We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state. (C) 2014 AIP Publishing LLC. Restricted Access Wed, 01 Jan 2014 00:00:00 GMT https://libjncir.jncasr.ac.in/xmlui/handle/10572/2538 2014-01-01T00:00:00Z https://libjncir.jncasr.ac.in/xmlui/handle/10572/2539 Nesting of thermodynamic, structural, and dynamic anomalies in liquid silicon Vasisht, Vishwas V.; Mathew, John; Sengupta, Shiladitya; Sastry, Srikanth Anomalous behaviour in density, diffusivity, and structural order is investigated for silicon modeled by the Stillinger-Weber potential by performing molecular dynamics simulations. As previously reported in the case of water [J. R. Errington and P. G. Debenedetti, Nature (London) 409, 318 (2001)] and silica [M. S. Shell, P. G. Debenedetti, and A. Z. Panagiotopoulos, Phys. Rev. E 66, 011202 (2002)], a cascading of thermodynamic, dynamic, and structural anomalous regions is also observed in liquid silicon. The region of structural anomaly includes the region of diffusivity anomaly, which in turn encompasses the region of density anomaly (which is unlike water but similar to silica). In the region of structural anomaly, a tight correlation between the translational and tetrahedrality order parameter is found, but the correlation is weaker when a local orientational order parameter (q(3)) is used as a measure of tetrahedrality. The total excess entropy and the pair correlation entropy are computed across the phase diagram and the correlation between the excess entropy and the regions of anomalies in the phase diagram of liquid silicon is examined. Scaling relations associating the excess entropy with the diffusion coefficient show considerable deviation from the quasi-universal behaviour observed in hard-sphere and Lennard-Jones liquids and some liquid metals. Excess entropy based criteria for diffusivity and structural anomalies fail to capture the observed regions of anomaly. (C) 2014 AIP Publishing LLC. Restricted Access Wed, 01 Jan 2014 00:00:00 GMT https://libjncir.jncasr.ac.in/xmlui/handle/10572/2539 2014-01-01T00:00:00Z