From Digital Colloids to Quasicrystals to Superconductors: Using Computational Methods to Discover, Visualize, and Design in Material Systems.

Carolyn L. Phillips
Seminar

Computational simulations are a rich environment for designing, visualizing, and discovering new phenomena in complex systems that can be inaccessible to theoretical and experimental studies.  In this research talk I will discuss three research areas where I have used simulation to study emergent behaviors in complex material systems.  

Digital Colloids are reconfigurable clusters made of N micron-sized colloidal particles bound flexibly to a central colloidal sphere have the capacity to store information.  I will discuss this new family of colloidal clusters, inspired by spherical codes, an ideal mathematical sequence of points corresponding to the densest possible sphere packings, and realized experimentally by a lock-and-key colloidal system.

Quasicrystals are ordered but not periodic structures whose discovery in 1982 challenged the traditional definition of what a crystal is. I will discuss how, using simulation, we discovered how a one-component system of particles with short range interactions can self-assembled an icosahedral quasicrystal, which previously never been observed in a non-atomic system, as well as other complex crystals with long-range order.  

In type-II superconductors, the magnetic field can penetrate the superconductor in the form of quantized vortices, flexible tubes that interact with each other and determine the response of the superconductor.  In time-dependent Ginzburg-Landau simulations of type-II superconductors, vortices are topological defects in the complex order parameter field.  We show that by interpreting a vortex as a subgraph of the dual graph of the four-dimensional  numerical space-time mesh of the simulation, vortices can be extracted over space and time and simulation events can equated to changes in the topology of the graph.

Bio:
Carolyn Phillips is a staff scientist in the Mathematics and Computer Science division at Argonne National Laboratory.  Dr. Phillips has a BS in Mathematics and a MS in Mechanical Engineering from MIT and a PhD in Applied Physics and Scientific Computing from the University of Michigan.  Dr. Phillips joined Argonne National Laboratory in 2012 as the Aneesur Rahman Postdoctoral Fellow.