Rigorous results on a first-order phase transition in antiferromagnetic spin-1/2 coupled chains

TL;DR

This paper provides rigorous theoretical results on a first-order quantum phase transition between dimerized and Haldane-type states in spin-1/2 coupled chains, including exact excited states and a partial phase diagram.

Contribution

It presents rigorous proofs of phase transition properties and exact excited states in spin-1/2 coupled chains with complex interactions.

Findings

Identified a first-order phase transition between two quantum states.

Derived exact excited states in both phases.

Discussed a partial phase diagram of the model.

Abstract

Some rigorous results are presented for a first-order quantum phase transition between the dimerized state and Haldane-type state (i.e., a state similar to the ground state of the one-dimensional spin-1 Heisenberg chain) in the spin-1/2 coupled chains with nearest-neighbour and next-nearest-neighbour Heisenberg interactions. Also presented are the exact excited states in both phases. A partial phase diagram of the general spin-1/2 coupled chains is discussed.