Exact ground states of frustrated quantum spin systems consisting of spin-dimer units

TL;DR

This paper derives models of frustrated quantum spin systems with exact ground states composed of various dimer configurations, including singlets, triplets, and spin-nematic states, using pseudo spin operators.

Contribution

It introduces several models with exact ground states of complex dimer arrangements, expanding understanding of frustrated quantum spin systems.

Findings

Exact ground states include dimer singlet and triplet products

Models incorporate dimer-spin-nematic states

Pseudo spin-1/2 operators are introduced for analysis

Abstract

We study frustrated quantum spin systems consisting of dimers of spin-1/2 spins. We derive several models that have the exact ground state of the form of the direct product of dimer states. The ground states realized include the product state of dimer singlets, that of dimer triplets with zero magnetization, those of dimer-spin-nematic states, and those of a mixture of the dimer states. Pseudo spin-1/2 operators emerging in each dimer are also introduced.