Matrix realignment and partial-transpose approach to entangling power of quantum evolutions
نویسندگان
چکیده
Given a unitary operator, in the context of quantum information 1 , one may ask how much entanglement capability the operator has. The entangling unitary operator can be considered as a resource for quantum-information processing, and it becomes important to quantitatively describe unitary operators. Recently, there is increasing interest in the entanglement capabilities of quantum evolution and Hamiltonians 2–10 . The entangling power based on the linear entropy 2 is a valuable, and relatively easy to calculate, measure of the entanglement capability of an operator. The entangling power for two qudits can be expressed in terms of operator entanglement 3,7 also called Schmidt strength 11 . Both entangling power and operator entanglement have been applied to the study of quantum chaotic systems 12–15 . Moreover, the concept of entangling power has been extended to the case with ancillas 16 , the case of entanglement-changing power 17 , and the case of disentangling power 18 . Let us start by introducing some basics of entanglement of quantum states, the operator entanglement, and the entangling power. For a two-qudit pure state Hd Hd, one can quantify entanglement by using the linear entropy
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