Quantum Phase Transition in Dimerized Spin-1/2 Chains

TL;DR

This paper investigates quantum phase transitions in dimerized spin-1/2 chains, revealing multiple critical points and entanglement phenomena influenced by external magnetic fields across various chain configurations.

Contribution

It provides new insights into entanglement behavior and critical points in dimerized spin chains, including open and anisotropic cases, under external magnetic fields.

Findings

Staircase structure in concurrence indicating multiple critical points

Entanglement emergence in weakly coupled spin pairs due to magnetic field

Analysis of both closed and open, isotropic and anisotropic chains

Abstract

Quantum phase transition in dimerized antiferromagnetic Heisenberg spin chain has been studied. A staircase structure in the variation of concurrence within strongly coupled pairs with that of external magnetic field has been observed indicating multiple critical points. Emergence of entanglement due to external magnetic field or magnetic entanglement is observed for weakly coupled spin pairs in the same dimer chain. Though closed dimerized isotropic XXX Heisenberg chains with different dimer strengths were mainly explored, analogous studies on open chains as well as closed anisotropic (XX interaction) chains with tilted external magnetic field have also been studied.