Zhu, Guo-Qiang; Du, Ke-Chun; Li, You-Quan - In: Physica A: Statistical Mechanics and its Applications 346 (2005) 3, pp. 295-302
We study the thermal entanglement and measure the entanglement in the hyperfine interaction of the hydrogen atom. We give the dependence of the entanglement on both the temperature and external magnetic fields.