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Unformatted text preview: April 7, 2005 Physics 681-481; CS 483: Assignment #6 Searching for one of 4 items (please hand in after the lecture, Thursday, April 21) We explore here Grovers algorithm when it is applied to identify one of only four items. This turns out to be a special case in two ways. (1) The probability of success after just a single query of the oracle turns out to be exactly 1. (2) The general procedure for constructing W = 2 | ih | - 1 out of Toffoli gates does not apply when the input register has only two qubits, and a different (simpler) construction must be used, special to the case | i = 1 2 ( | 00 i + | 01 i + | 10 i + | 11 i ) . 1. To convince yourself that Grovers algorithm is not entirely uninteresting when N = 4, note that if you have a classical oracle that indicates which of four items is special, all you can do is apply the oracle to one randomly selected item after another. What is the mean number of queries of the classical oracle required to determine which item is special?mean number of queries of the classical oracle required to determine which item is special?...
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This note was uploaded on 09/28/2008 for the course PHYS 481 taught by Professor Anon during the Spring '05 term at Cornell University (Engineering School).
- Spring '05