Professor J Halley

CSENG Physics & Astronomy
College of Science & Engineering
Twin Cities
Project Title: 
Simulations in Chemical and Condensed Matter Physics

This group studies a variety of complex many body systems providing insight at many length and time scales into the collective phenomena of interest.

  • A current focus is on abstracted models of interacting polymer systems far from equilibrium in which they are accumulating data on the statisitcal distribution of chemical morphologies and dynamics. These models are intended to provide better understanding of how dynamic metastable states involving large molecules can emerge from a starting configuration of small molecules as is believed to have occurred in the origin of life. The researchers have studied a "well mixed reactor" version of such a model, an extension in which spatial heterogeneity and diffusion can occur and a model in which bond energies and energy flows are taken into account. Studies of the detailed morphological and dynamic character of the well mixed model also continue. Measures for characterizing lifelike properties of such systems have been developed and tested on real living and nonliving systems. The group found evidence that spontaneous generation of population distributions like those in living systems is most likely in quite sharply defined circumstances specified by temperature and bond energies.
  •  A second focus is on the behavior of oxide water interfaces using in-house self consistent tightbinding codes. There is tremendous current interest  in oxides as electrodes in a variety of technologies using aqueous electrolytes including fuel cells, batteries and electrolysers. Water-oxide interfaces are also a key component in corroding metal surfaces so such studies are also relevant to attempts to understand and inhibit corrosion. One project simulates titania water interfaces with particular emphasis on new methods for calculating surface energies to understand the propensity of titania water interfaces to dissociate water.
  • A third interest is quantum fluid phenomena. A current emphasis is on condensate mediated transmission using Diffusion Monte Carlo methods to obtain informaton about excited scattering states in the  strongly interacting helium four superfluid. The methods are unique and were developed by this group. Earlier published results used a guiding wave function which did not conserve particle current. The current project is to use an improved guiding wave function which removes that defect. The project is relevant to an experiment this group proposed more than a decade ago and which has been tried in various laboratories, still without a definitive result, to observe the condensate mediated transmission effect. Another quantum fluids project, carried on at a low intensity level, is the exploration of effects of disorder, and in particular of disorder induced pairing, in superconductors.

Project Investigators

Professor J Halley
Post-Doctoral Research Associate Ben Frederick Intoy
Shuhui Luo
Abrar Quadery
Noah Rogers
Subhodip Saha
Mr. Patrick Schelling
Qianyi Sheng
Dr. Aaron Wynveen
 
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