University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Friday, May 19th 2017
12:20 pm:
Special Seminar in PAN 110
Speaker: Yuan Wan, Perimeter Institute for Theoretical Physics
Subject: Generation and control of non-equilibrium landscape in a frustrated magnet

Geometrically frustrated magnets often possess accidentally degenerate ground states at zero temperature. At low temperature, thermal fluctuations lift the accidental degeneracy and stabilize ground states with maximal entropy. This phenomenon, known as “order by disorder”, underlines the fluctuation contribution to the free energy landscape in frustrated magnets.

In this talk, I show that such free energy landscape may be controlled in a non-equilibrium setting. This is owing to the fact that the slow motion along the ground state manifold is governed by the fast modes deviating away from the manifold. I will demonstrate this idea on a model system, namely the classical pyrochlore XY antiferromagnet, where exciting the fast modes produces a tuneable effective free energy landscape with minima located at thermodynamically unstable states. I will also discuss the implications on pyrochlore antiferromagnet materials such as Er2Ti2O7 and NaCaCo2F7.

Faculty Host: Natalia Perkins

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