Maximal thermal entanglement using three-spin interactions

Three-spin interactions in three-qubit systems at thermal equilibrium can be used for simple and efficient creation of maximally entangled states. We do not require set of gates to achieve this goal; rather, maximal thermal entanglement naturally arises by appropriately tuning the interactions present in the system. Within the broad range of parameter regimes found, we identify the ones accessible in triple quantum dot and triangular optical lattice, thus opening a way toward simple implementation of maximally entangled states with different types of three-spin interactions. Our results suggest tight connection between the presence of W type of entanglement and magnetization, enabling experimental detection of the W state.