Talk:Deutsch–Jozsa algorithm

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I found a small mistake in the description of the algorithm, and I corrected it. To me, the wording of the article is still a bit sloppy; but I'm not going to try to fix it at the moment. At least now the algorithm works. :) Karadoc** 05:27, 3 July 2006 (UTC)Reply

what we measuring?

As wrot there "Definition: A quantum algorithm to determine whether a function is constant or balanced, that is, returns 1 for half the ___domain and 0 for the other half. For a function taking n input qubits, first, do Hadamards on n 0's, forming all possible inputs, and a single 1, which will be the answer qubit. Next, run the function once; this exclusive or's the result with the answer qubit. Finally, do Hadamards on the n inputs again, and measure the answer qubit. If it is 0, the function is constant, otherwise the function is balanced. - http://www.nist.gov/dads/HTML/deutschJozsaAlgo.html" - need measure only one the answer qubit, but how wrote at wikipedia "The algorithm is as follows. First, do a Hadamard transform on a quantum register of n 0s, forming all possible inputs, and a single 1, which will be the answer qubit. Next, run the function once. This is done by using the n input qubits as input of the function of a Function-Controlled NOT gate that works on the answer qubit. Finally, do Hadamards on the n inputs again, and measure them". So what we have measure answer qubit or over all except answer qubit. And if we must measure answer qubit, then why we must do hdamard transform (after then qubits pass through CNOT gate) on qubits that not be measured?