Dr. Greg Fiete received his BS in physics with Highest Honors from Purdue University, and his PhD in theoretical condensed matter physics from Harvard University in 2003. He completed postdoctoral work at the Kavli Institute for Theoretical Physics on the campus of the University of California, Santa Barbara and also at the California Institute of Technology as a Lee A. DuBridge Prize Fellow in Theoretical Physics.

Dr. Fiete’s interests in condensed matter physics span a wide range of topics, but focus primarily on the quantum behavior of strongly correlated electrons. One of the central goals is to understand what types of novel and unexpected behaviors can arise from the interplay of quantum mechanics and strong correlations. Such issues underlie our current understanding of frustrated magnets, quantum wires, and behavior of two-dimensional electrons in a strong perpendicular magnetic field.

One of the remarkable features of strongly correlated electrons in reduced dimensions is “fractionalization” where the electron essentially splinters apart. How this happens depends on the situation and the spatial dimension (one dimension vs. two dimensions) of the problem. In one dimension spin and charge become essentially distinct degrees of freedom: when an electron is placed into a one dimensional “metal,” the spin of that electron and its charge propagate away with different speeds! A surprising result given we are used to thinking of electrons as having quantized spin and charge. Recent experiments have unambiguously proven this is indeed how one dimensional electrons behave. Two dimensional electron gases subject to a strong perpendicular magnetic field may display the “fractional quantum Hall effect” if the mobility of the electrons is high enough. In this effect, the Hall conductance is quantized at special values and the excitations of the system carry charge in certain fractions (determined by the value of the Hall conductance) of the electron’s charge. This result too is borne out in experiment.

The (fractional) quantum Hall effect created something of a revolution in condensed matter physics because of its many novel features not anticipated from any previous study. One of the most remarkable features is a topological aspect of the quantum mechanics. Since topology is a global property, local perturbations leave the quantum properties essentially unchanged, hence they tend to be robust against decoherence, a feature that may turn out to have implications in areas such as the burgeoning field of “topological quantum computation.” Certain types of band insulators, magnets, and superconductors are also believed to possess topological properties, and there are certainly others. One of Dr. Fiete’s current research interests is looking for new venues to realize topological aspects of quantum matter and work out their implication for various experiments.