Quantum critical behavior of deconfined spinons

Note: 10:00 AM
Speaker: Flavio Nogueira, Freie Universitat, Berlin, Germany

When: February 24, 2010 (Wed), 10:00AM to 11:00AM (add to my calendar)

This event is part of the Condensed Matter Theory Seminar Series.

Abstract: In the same way as quarks are the elementary constituents of
different types of particles, spinons may be
thought as the the elementary constituents of different order parameters
in a Mott insulator. Examples are the Neel and
valence-bond solid (VBS) order parameters. Like the quarks in ordinary
matter, the spinons are confined in the
Neel and VBS phases. There are situations where a second-order quantum
phase transition between these two phases
occurs and the system exhibits a quantum critical point (QCP). At the
QCP the spinons are deconfined and determine completely the
quantum critical behavior of the Mott insulator. In this talk I will
discuss some important aspects of
deconfined spinons at quantum criticality. For example, I will explain
why the anomalous dimension of the Neel order
parameter should be large, which is one of the main properties of
systems where the quantum critical behavior is
governed by deconfined spinons. The interplay between deconfined spinons and doping in a Mott insulator will also be
discussed.