CSE 599d - Quantum Computing Reversible Classical Circuits and the Deutsch-Jozsa Algorithm

Now that we’ve defined what the quantum circuit model, we can begin to construct interesting quantum circuits and think about interesting quantum algorithms. We will approach this task in basically an historical manner. A few lectures ago we saw Deutsch’s algorithm. Recall that in this algorithm we were able to show that there was a set of black box functions for which we could only solve Deutsch’s problem by querying the function twice classically, but when we used the boxes in their quantum mode, we only needed to query the function once. Now this was certainly exciting. But one query versus two query is a lot like getting half price for a matinee. Certainly it is a great way to save money, but its no way to build a fortune (Yeah, yeah, you can go on all you want about Ben Franklin, but a penny saved is most of the time a waste of money these days.) In the coming lectures we will begin to explore generalizations of the Deutsch algorithm to more qubits. For it is in the scaling of resources with the size of the problem that our fortunes will be made (or lost.)