Uncovering the 'hidden' structural order in dense liquids and glasses
ABSTRACT :
The conventional wisdom is that liquids are completely disordered and lack nontrivial structure beyond nearest-neighbor distances. Using colloidal suspensions as a model system to probe the structure and dynamics of liquids and glasses in real space and at single-particle resolution, I will present experimental findings that upend this view and reveal that the structural order in these systems is, in fact, unusually rich. In the first part of my talk, I will briefly describe experiments where we will use machine-learning techniques to show that the structure hidden in a glass decides its stability against crystallization [1]. In the second part of my talk, using a recently introduced four-point correlation function, we will show that colloidal liquids have a highly nontrivial structure comprising alternating layers with icosahedral and dodecahedral order that grows with supercooling and governs the particle dynamics [2, 3].
ABOUT THE SPEAKER:
Rajesh Ganapathy obtained his M.Sc. in Physics from IITM in 1999. He worked for a year in the Laundry Cleaning Department (fondly called 'Dhobi Ghat' ) at the Hindustan Unilever Research Centre in Bangalore, where he worked on optimizing the formulation of Surf detergent. This is also where he gained his first formal exposure to soft matter. From 2000- 2006, he was a Ph.D. student in Ajay Sood's lab at the Dept. of Phys. Indian Institute of Science, Bangalore. He was a postdoctoral fellow at Cornell from 2007-2009. He has been at JNCASR since 2009. Rajesh's research interests span colloidal and granular liquids, crystals, and glasses, active matter, shear-induced transitions, condensed matter on non-Euclidean surfaces, surface growth, and stochastic heat engines.