Dr. Rajesh Narajanan, INT

Titel: Quantum Critical Behavior in Itinerant Magnets.

Abstract:

Quantum Phase Transitions (QPT) are phase transitions that occur at zero temperature as a function of a non-thermal control parameter. This talk deals with the quantum phase transitions in itinerant electronic systems. We will show how the traditional folklore of the QPT's being described by a mean field critical behavior is seriously flawed for the itinerant systems.

The fallacy stems from the fact that in itinerant systems there are soft or slow modes that exist in addition to the order-parameter modes.

These soft-modes couple to the order-parameter modes and profoundly effect the critical properties. How exactly the soft-modes actually alter the critical behavior will be made clear during the course of this presentation. We will conclude with a list of open challenges that remain to be tackled in this field.