Complete 3-Qubit Grover search on a programmable quantum computer

C Figgatt,C Monroe,S Debnath,N M Linke,K A Landsman,D Maslov

doi:10.1038/s41467-017-01904-7

Abstract

The Grover quantum search algorithm is a hallmark application of a quantum computer with a well-known speedup over classical searches of an unsorted database. Here, we report results for a complete three-qubit Grover search algorithm using the scalable quantum computing technology of trapped atomic ions, with better-than-classical performance. Two methods of state marking are used for the oracles: a phase-flip method employed by other experimental demonstrations, and a Boolean method requiring an ancilla qubit that is directly equivalent to the state marking scheme required to perform a classical search. We also report the deterministic implementation of a Toffoli-4 gate, which is used along with Toffoli-3 gates to construct the algorithms; these gates have process fidelities of 70.5% and 89.6%, respectively.

Highlights

The Grover quantum search algorithm is a hallmark application of a quantum computer with a well-known speedup over classical searches of an unsorted database
We implement the Grover search algorithm using a scalable trapped atomic ion system[15] on n = 3 qubits, which corresponds to a search database of size N = 2n = 8
We examine two alternative methods of encoding the marked state within the oracle

Summary

Introduction

The Grover quantum search algorithm is a hallmark application of a quantum computer with a well-known speedup over classical searches of an unsorted database. The algorithm is performed with both a phase oracle, which has been previously demonstrated on other experimental systems, and a Boolean oracle, which requires more resources but is directly comparable to a classical search. D General circuit diagram for a Grover search algorithm using a phase oracle.

Results

Conclusion