Entanglement in the one-dimensional Kondo necklace model

Abstract
We discuss the thermal and magnetic entanglement in the one-dimensional Kondo necklace model. First, we show how the entanglement naturally present at zero temperature is distributed among pairs of spins according to the strength of the two couplings of the chain, namely, the Kondo exchange interaction and the hopping energy. The effect of temperature and the presence of an external magnetic field are then investigated. We also discuss the adjustment of these variables in order to control the entanglement available in the system. In particular, it is indicated that there exists a critical magnetic field above which the entanglement undergoes a sharp variation, leading the ground state to a completely unentangled phase.