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Entanglement changing power of two-qubit unitary operations

M. -Y. Ye·Dong Sun·Y. -S. Zhang·G. -C. Guo
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Abstract

We consider a two-qubit unitary operation along with arbitrary local unitary operations acts on a two-qubit pure state, whose entanglement is C_0. We give the conditions that the final state can be maximally entangled and be non-entangled. When the final state can not be maximally entangled, we give the maximal entanglement C_max it can reach. When the final state can not be non-entangled, we give the minimal entanglement C_min it can reach. We think C_max and C_min represent the entanglement changing power of two-qubit unitary operations. According to this power we define an order of gates.

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M. -Y. Ye, Dong Sun, Y. -S. Zhang, G. -C. Guo. 2004-03-23. Entanglement changing power of two-qubit unitary operations. https://doi.org/10.1103/physreva.70.022326

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