Nov 28 2012 Wednesday 15:30
Muhittin Mungan, Boğaziçi University
How things rupture - Avalanches in an exactly solvable charge density wave system

Abstract:Charge density wave (CDW) systems refer to elastically-coupled particle systems, in which each particle is subject to a periodic potential with a random phase-offset. When driven by an external driving force, CDWs exhibit a depinning transtion: there is a threshold force F_T, such that for F < F_T all configurations are static (pinned), while for F > F_T the CDW slides. The depinning transition occurs through a succession of avalanches during which increasingly larger segments of the pinned configuration are being destabilized and move to new equilibrium configurations. This process is accompanied by a accumulation and release of stresses until a configuration is reached that is no longer sustainable against further increase of the driving force and the system is depinned.

It has been argued long time ago that the depining transition of CDWs constitutes a dynamic critical phenomenon. In this talk we will motivate and present a CDW system that is simple enough to submit to analytical treatment, yet complex enough to capture all the features of criticality near threshold.

This is joint work with David Kaspar (UC Berkeley).