Quantum discord for a central two-qubit system coupled to an XY spin chain with multipartite interaction

Quantum discord of two central qubits coupled to an XY spin chain with three-spin interaction in a transverse magnetic field is investigated. Quantum discord decreases dramatically around the critical point α=0.5α=0.5 without the external magnetic field and around λ=1λ=1 without the three-spin interaction. Here, αα denotes the strength of the three-spin interaction and λλ is the strength of the external magnetic field. If the three-spin interaction is switched on, the significant change position of quantum discord has a 2α2α displacement from the original position. Our results reveal that quantum discord could be used to spotlight the critical point of quantum phase transition, detect both the existence and strength of three-spin interaction.

The significant change position of quantum discord has a 2α2α (αα denotes the strength of the three-spin interaction) displacement from the original position.Figure optionsDownload as PowerPoint slideHighlights
► Quantum discord could be used to spotlight the critical point of quantum phase transition.
► Quantum discord could detect the existence and the strength of three-spin interaction.
► The effect of the parameters on quantum discord has also been considered.