Quantum Entanglement in Trimer Clusters

Quantum entanglement is a measure of quantum correlations which are responsible for effective work of quantum devices (in particular, quantum computers), significantly outperforming their classical counterparts.(1) Here, we investigate quantum entanglement in the trimer clusters consisting of three electron spins sited in vertexes of an isosceles triangle. We consider entanglement of two subsystems of the system. The first subsystem consists of spins sited on the triangle baseline and the second subsystem consists of a spin equidistant from others. We generalized the Bleany-Bowers equation(2,3) for trimer clusters. It is shown that entanglement can emerge only in the case of the antiferromagnetic interaction of the subsystems. An equation for the temperature of the entanglement emergence is derived. The criterion of the double negativity' is used in order to find the dependence of the entanglement on the temperature.