The quantum spin quadrumer

Datum

15.09.2017

Zeit

10:30 - 11:30

Sprecher

Dr. Ganesh Ramachandran

Zugehörigkeit

The Institute of Mathematical Sciences, Chennai, India

Sprache

en

Hauptthema

Materialien

Andere Themen

Materialien, Physik

Host

Grit Rötzer

Beschreibung

A fundamental motif in frustrated magnetism is the N-spin cluster with the Hamiltonian $H = vec{S}_{tot}^2$, where $vec{S}_{tot}$ is the sum of all the N spins. Examples include (N=2) dimerized systems, (N=3) Kagome antiferromagnets and (N=4) spin ice systems. For N=2,3, such systems have been fruitfully studied using semi-classical large-S field theories. We present the appropriate theory for the N=4 case. Unlike N=2 and 3, the N=4 cluster has rich topological features. In particular, its ground state space has non-manifold character with extra soft modes appearing at isolated points. We show that in the low-energy limit, the N=4 cluster decouples into a free spin-S spin and a rigid rotor. This provides an elegant way to understand its spectrum and physical properties.

Links

• Seminars at the IFW

Letztmalig verändert: 15.09.2017, 09:59:26