A dipolar coupled spin system can achieve internal thermodynamic equilibrium states at negative absolute temperature. We study analytically and numerically the temperature dependence of the concurrence in a dipolar coupled spin-1/2 system in both nonzero and zero fields and show that, at negative temperatures, entangled states can exist even in zero magnetic field.
- Dipole-dipole interactions
- Negative temperature
- Zero field
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)