Estimation of quantum correlations in magnetic materials by neutron scattering data

• We predict macroscopic quantum correlations in VODPO4 ⋅ 0.5D2O by analyzing neutron scattering experimental data.
• The critical temperature of VODPO4 ⋅ 0.5D2O can reach as high as 82.5 K, where entanglement drops to 0.
• Quantum discord can even survive at room temperature.
• Entanglement can be enhanced and the critical temperature increases with the strength of DM interaction.

We demonstrate that inelastic neutron scattering technique can be used to indirectly detect and measure the macroscopic quantum correlations quantified by both entanglement and discord in a quantum magnetic material, VODPO4⋅12D2O. The amount of quantum correlations is obtained by analyzing the neutron scattering data of magnetic excitations in isolated V4+ spin dimers. Our quantitative analysis shows that the critical temperature of this material can reach as high as Tc=82.5 KTc=82.5 K, where quantum entanglement drops to zero. Significantly, quantum discord can even survive at Tc=300 KTc=300 K and may be used in room temperature quantum devices. Taking into account the spin–orbit (SO) coupling, we also predict theoretically that entanglement can be significantly enhanced and the critical temperature TcTc increases with the strength of spin–orbit coupling.