Entangling power and local invariants of two-qubit gates

Abstract

We show a simple relation connecting entangling power and local invariants of two-qubit gates. From the relation, a general condition under which gates have the same entangling power is derived. The relation also helps in finding the lower bound of entangling power for perfect entanglers, from which the classification of gates as perfect and nonperfect entanglers is obtained in terms of local invariants.