Noise Analysis of Grover's Quantum Search Algorithm

Abstract

For searching an item in unstructured databases, Grover's quantum search algorithm offers quadratic speedup over classical search algorithms. This paper reports 2 to 5 quantum-bit (Qubit) implementations of Grover's search algorithm using the phase-flip method for oracle function realization without any extra ancilla qubit. A comprehensive estimation and analysis of the theoretical and physical accuracies of the algorithm have been presented. The impact of increasing qubits on accuracy has been computed and analyzed. The metrics delineated for comparison are the number of qubits and gates, depth of the circuit, execution time, and theoretical/physical accuracy. The results revealed a greater disparity between theoretical and physical accuracy using a higher number of qubits perceived to be caused by noisy qubits utilized in computations. The novelty of the work is the investigation of variations caused by the noise in the accuracy and execution time of Grover's search algorithm. The results indicate that because of noise, the accuracy of 2- and 3- qubit implementations declined by 14.49% and 33.86%, whereas the execution time increased by 50% and 80%; respectively.