RUI: Computational Studies of Spin-Polarized Quantum Fluids and Solids

University Of Wisconsin-La Crosse, La Crosse WI

Investigators

Abstract

0071706 Ragan This is an RUI award to support numerical and analytical approaches to study the spin dynamics of paramagnetic quantum fluids and solids. The research consists of two parts: analysis of spin-wave instabilities in spin-echo experiments, and computer simulation of spin diffusion in solid helium-3. The first part involves the detailed computer simulation and analysis of NMR experiments currently being planned at the National High Magnetic Field Laboratory to detect the long predicted, and recently disputed, zero temperature attenuation of transverse spin currents in spin-polarized Fermi liquids. This effort builds on previous progress and the results should be key in assessing the validity of data obtained in future experiments at ultra-low temperatures and high magnetic fields. The second project will lend computational support to recent attempts by Cowan and Mullin to use linear response theory to calculate spin diffusion coefficients in spin-polarized solid helium-3. In the calculation, a method originated by Kubo is used to relate the long-time diffusive behavior of the spin-correlation function to the local interactions at microscopic time scales. The goal of this project is to assess the validity of this method by calculating the spin correlation function using molecular dynamics simulations from initial conditions generated with Monte Carlo techniques. The bulk of the computations will be performed on the IBM SP at the San Diego Supercomputer Center. Undergraduates will participate in these calculations as part of the university commitment to undergraduate research participation and as part of the Computational Physics Emphasis. %%% This is an RUI award to support numerical and analytical approaches to study the spin dynamics of paramagnetic quantum fluids and solids. The research consists of two parts: analysis of spin-wave instabilities in spin-echo experiments, and computer simulation of spin diffusion in solid helium-3. Undergraduates will participate in these calculations as part of the university commitment to undergraduate research participation and as part of the Computational Physics Emphasis. ***