On the non-existence of a universal Hadamard gate
نویسنده
چکیده
We establish the non-existence of a universal Hadamard gate for arbitrary unknown qubits, by considering two different principles; namely, no-superluminal signalling and non-increase of entanglement under LOCC. It is also shown that these principles are not violated if and only if the qubit states are of the special form obtained in our recent work [IJQI (in press), quant-ph/0505068].
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تاریخ انتشار 2006