Complex Properties of Disordered Quantum Systems

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This award supports computational and theoretical research on classical and quantum complex systems. The PI will study quantum complex systems and their classical analogs with an aim to elucidate the relationship between them. Research will focus on understanding how the low energy states of the two-dimensional +J/-J Edwards-Anderson spin glass model change when quantum-mechanical tunneling is introduced. The PI will exploit a computational algorithm developed to find all the ground states of the classical model to enable the calculation of exact quantum eigenstates of much larger system sizes than can be computed by other methods, in the limit of small tunneling amplitudes. Preliminary results reveal that the quantum ground states have a complex and rich structure that will be elucidated further in the proposed research. The method is also being used to compare the effects of quantum tunneling to other (classical) physical perturbations, such as coupling to a deformable lattice. %%% This award supports computational and theoretical research and education on classical and quantum complex systems. The PI will use a model of a spin glass to study the relationship between quantum complex systems and their classical analogs. This work is of fundamental importance to the fields of statistical mechanics and condensed matter physics. It also contributes to efforts to control and manipulate quantum mechanical states; such a capability may have long term impact on information and communication technologies. ***