ICAM Discussion
Professor Robert J. Schrieffer
NHMFL/Florida State University
Department of Physics
1800 East Paul Dirac Drive
Tallahassee, FL 32310
(850) 644-3203
(850) 644-5038 FAX
Candidate areas for ICAM
1. Quantum phase transitions, Antiferromagnetism to superconductivity
This area is of high current interest. It involves low frequency modes with are nonlinear. It is proposed that such transitions are related to other soft mode transitions.
2. Spin glass transitions are of interest because of
many competing states as in biological systems.
3. Time dependent slowing down effects are of importance as well as correlation length
variation near critical points.
An important soft mode transition is that between antiferromagnetism (AF) and superconductivity (SC) in HTS materials such s La2-x Sr2 Cu O4. In these systems the characteristic frequency for AF fluctuation decreases as one reaches the critical doping xc at which long range AF order vanishes. This is one example of a quantum critical point in which two types of order compete for long range order with low frequencies being involved. In these materials there is strong coupling between the spin fluctuation propagator and the fermion dynamics. While renormalization group methods have been applies to these problems, it would be useful to place these problems in a broader contact in which phase transition occur between two states, each with long range order.