Entanglement and quantum correlations in the XX spin-$1/2$ honeycomb lattice

TL;DR

This study investigates quantum correlations like concurrence and quantum discord in the XX honeycomb spin-1/2 model, revealing their effectiveness in identifying quantum critical points and exploring magnetic-entanglement behavior.

Contribution

It applies Lanczos and DMRG techniques to analyze quantum correlations in the model, highlighting their role in detecting phase transitions and entanglement phenomena.

Findings

Quantum correlations identify quantum critical points.

Concurrence and QD are short-range but indicate long-range critical correlations.

Magnetic-entanglement behavior emerges near saturation field.

Abstract

The ground state phase diagram of the dimerized spin-1/2 XX honeycomb model in presence of a transverse magnetic field (TF) is known. With the absence of the magnetic field, two quantum phases, namely, the N\'eel and the dimerized phases have been identified. Moreover, canted N\'eel and the paramagnetic (PM) phases also emerge by applying the magnetic field. In this paper, using two complementary numerical exact techniques, Lanczos exact diagonalization, and Density matrix renormalization group (DMRG) methods, we study this model by focusing on the quantum correlations, the concurrence, and the quantum discord (QD) among nearest-neighbor spins. We show that the quantum correlations can capture the position of the quantum critical points in the whole range of the ground state phase diagram consistent with previous results. Although the concurrence and the QD are short-range, informative about long-ranged critical correlations. In addition, we address a "magnetic-entanglement" behavior that starts from an entangled field around the saturation field.