Magnetization of Antiferromagnetic Cactus Graph Model with Exact Dimer Ground State

Abstract

We introduce and explore the magnetization behavior in a quantum spin system on a cactus graph, deemed the Cactus Graph Model (CGM), featuring an exact dimer singlet ground state. We analyze the singlet-triplet gap, interactions among excited triplets, and correlated hopping under an external magnetic field using a strong coupling expansion. Employing an effective hard-core boson representation, we unveil density wave magnetization plateaus and supersolid phases, revealing the intricate interplay between interactions and hopping dynamics. Furthermore, we conjecture that correlated hopping gives rise to multi-triplet bound states, and potentially engendering to the stabilization of additional low-lying magnetization plateaus.