JournalsprimsVol. 27 , No. 4DOI 10.2977/prims/1195169424

On Ground State Degeneracy of <i>Z</i><sub>2</sub> Symmetric Quantum Spin Models

  • Taku Matsui

    Tokyo Metropolitan University, Japan
On Ground State Degeneracy of <i>Z</i><sub>2</sub> Symmetric Quantum Spin Models cover

Abstract

We consider a class of _Z_2 symmetric quantum spin Hamiltonians. Anisotropic spin 1/2 Heisenberg models are typical examples. Proof of groound state degeneracy (_Z_2 symmetry breaking), construction of pure gournd states are given in a systematic way.