Physics Seminar: Ordered vs. Disordered States of the Random-field Model in Three Dimensions
September 24, 2015 @ 12:00 pm
Place: Namm 823
Thursday, September 24 at 12:00 PM
Presented by Prof. Dmitry Garanin
Faculty and students are welcome, light refreshments will be served.
Talk reports on recent numerical investigation of the glassy behavior of random-field exchange models in three dimensions. Correlation of energy with the magnetization for different numbers of spin components has been studied. There is a profound difference between the models with two and three spin components with respect to the stability of the magnetized state due to the different kinds of singularities: vortex loops and hedgehogs, respectively. Memory effects pertinent to such states have been investigated. Insight into the mechanism of the large-scale disordering is provided by numerically implementing the Imry-Ma argument in which the spins follow the random field averaged over correlated volumes. Thermal stability of the magnetized states is investigated by the Monte Carlo method.