kivelson_steven

Steven A. Kivelson

Professor of Physics

Research areas:

Description

Condensed Matter Physics

I am interested in the qualitative understanding of the macroscopic and collective properties of condensed matter systems, and on the relation between this and the microscopic physics at the single electron or single molecule scale. I have been particularly interested in exploring the spectacular consequences of strong correlation effects in electronic materials and devices where the low energy properties are qualitatively different from those of a non interacting electron gas. This field of study has been made particularly rich and exciting by the seemingly nonending sequence of unexpected experimental discoveries that have occurred in this field over the past couple of decades - discoveries which undermine accepted beliefs and raise conceptually deep questions concerning the emergent behavior of systems with many strongly interacting degrees of freedom. Prime examples of this on which I have focused my attentions are: • The amazing electronic properties of the cuprate perovskites including high temperature superconductivity, quantum antiferromagnetism, and the delicate interplay between superconducting, charge-density-wave, and spin-density wave ordering; • The two dimensional electron-gas in a strong magnetic field, which exhibits phenomena associated with the quantum Hall effect, fractional charge, and fractional statistics. Presently, I am actively pursuing the implications of a theoretical proposal my collaborators and I have recently made concerning the existence and character of a variety of zero temperature phases of correlated electronic systems. These phases occur as groundstates of interacting electrons in regimes intermediate between the weakly correlated Fermi gas phase observed in conventional metals, and the insulating "Wigner Crystalline" phases which occur when the interactions are large compared to the Fermi energy. We have named these phases "electronic liquid crystalline" in analogy with the intermediate phases observed in the thermal phase diagram of molecular liquids. Some of them have apparently already been observed, recently, in high temperature superconducting materials and in quantum Hall devices. In addition, I am involved with developing a new approach to understanding the old, but certainly unsolved problem of the glass transition in supercooled liquids. It is my feeling that to obtain a qualitative understanding of these physically important problems, it is vital to obtain exact, and well controlled approximate solutions of simplified model problems which properly caricature the important physics, and this has dictated the use of field-theoretic methods which are based on the renormalization group viewpoint of interacting systems.

Courses Taught