Quantum entanglement in mixed-spin trimer: Effects of a magnetic field and heterogeneous g-factors

TL;DR

This paper analyzes how non-conserving magnetization influences quantum entanglement in a mixed-spin trimer with heterogeneous g-factors, revealing significant entanglement enhancement and controllability via magnetic fields.

Contribution

It provides an analytical diagonalization of the Hamiltonian for a mixed-spin trimer with non-conserving magnetization and explores its effects on quantum entanglement, highlighting the role of g-factor differences.

Findings

Non-conserving magnetization causes continuous entanglement dependence on magnetic field.

Small differences in g-factors can enhance entanglement up to 7-fold.

Entanglement can be manipulated broadly through magnetic field adjustments.

Abstract

Mixed spin-(1/2,1/2,1) trimer with two different Land\'{e} g-factors and two different exchange couplings is considered. The main feature of the model is non-conserving magnetization. The Hamiltonian of the system is diagonalized analytically. We presented a detailed analysis of the ground state properties, revealing several possible ground state phase diagrams and magnetization profiles. The main focus is on how non-conserving magnetization affects quantum entanglement. We have found that non-conserving magnetization can bring to the continuous dependence of the entanglement quantifying parameter (negativity) on magnetic field within the same eigenstate, while for the case of uniform $g$-factors it is a constant. The main result is an essential enhancement of the entanglement in case of uniform couplings for one pair of spins caused by an arbitrary small difference in the values of $g$-factors. This enhancement is robust and brings to almost 7-fold increasing of the negativity. We have also found weakening of entanglement for other cases. Thus, non-conserving magnetization offers a broad opportunity to manipulate the entanglement by means of magnetic field.