A New Entanglement Measure Induced By the

Introduction Quantum information processing has received a considerable interest in the last years, induced by the possibility of teleporting an unknown quantum state and building a quantum computer. Also new questions on the relation of quantum and classical physics arise in this context. The feature which makes quantum computation more ecient than classical computation and allows teleportation is entanglement. Therefore there is also an increasing interest in quantifying entanglement [1]. Our letter considers the quantication by introducing a new entanglement measure. For pure states on the tensor product of two Hilbert spaces a measure is given by the entanglement of entropy. Let T be the set of states on the tensor product of two Hilbert spaces H H 2 , i.e. the set of all positive trace class operators with trace 1. For a pure state 2 T , the entanglement of entropy E() is given by E() := tr ( 1 log 2 1 ) = tr ( 2 log 2 2 ) = j i j log 2 j i j where