Dynamics of quantum discord of two coupled spin-1/2 subjected to time-dependent magnetic fields

TL;DR

This paper investigates how quantum discord evolves over time in a two-spin-1/2 system under controllable magnetic fields, revealing complex oscillations and comparing it with entanglement dynamics.

Contribution

It provides an exact analytical description of quantum discord dynamics for mixed states in a two-spin system with time-dependent magnetic fields.

Findings

Quantum discord exhibits complex oscillatory behavior over time.

The interplay between magnetic fields and spin coupling affects quantum correlations.

Comparison shows differences between discord and entanglement evolution.

Abstract

We describe the dynamics of quantum discord of two interacting spin-1/2 subjected to controllable time-dependent magnetic fields. The exact time evolution of discord is given for various input mixed states consisting of classical mixtures of two Bell states. The quantum discord manifests a complex oscillatory behaviour in time and is compared with that of quantum entanglement, measured by concurrence. The interplay of the action of the time-dependent magnetic fields and the spin-coupling mechanism in the occurrence and evolution of quantum correlations is examined in detail.