2005/08/31 by Christopher L. Henley · 2 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Ground state #Hamiltonian (control theory) #Heisenberg model #Ising model #Physics #Physics of Superconductivity and Magnetism #Pyrochlore #Quantum many-body systems #Quantum mechanics #Spinon #Spins #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.96.047201
4pp, one figure
arxiv created 2005/08/31 · openalex publication_date 2006/01/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The (three-dimensional) pyrochlore lattice antiferromagnet with Heisenberg spins of large spin length S is a highly frustrated model with a macroscopic degeneracy of classical ground states. The zero-point energy of (harmonic-order) spin-wave fluctuations distinguishes a subset of these states. I derive an approximate but illuminating effective Hamiltonian, acting within the subspace of Ising spin configurations representing the collinear ground states. It consists of products of Ising spins around loops, i.e., has the form of a Z2 lattice gauge theory. The remaining ground-state entropy is still infinite but not extensive, being O(L) for system size O(L3). All these ground states have unit cells bigger than those considered previously.