Error tolerance in an NMR Implementation of Grover's Fixed-Point Quantum Search Algorithm

We describe an implementation of Grover's fixed-point quantum search algorithm on a nuclear magnetic resonance (NMR) quantum computer, searching for either one or two matching items in an unsorted database of four items. In this new algorithm the target state (an equally weighted superposition of the matching states) is a fixed point of the recursive search operator, and so the algorithm always moves towards the desired state. The effects of systematic errors in the implementation are briefly explored.Comment: 5 Pages RevTex4 including three figures. Changes made at request of referees; now in press at Phys Rev