Speed-up and entanglement in quantum searching

Authors:
Samuel L. Braunstein;Arun K. Pati
Affiliations:
Informatics, Bangor University, Bangor, UK;Institute of Physics, Sainik School Post, Orissa, India
Venue:
Quantum Information & Computation
Year:
2002

Citing 1
Cited 3

Algorithms for quantum computation: discrete logarithms and factoring

SFCS '94 Proceedings of the 35th Annual Symposium on Foundations of Computer Science

Quantum computing without entanglement

Theoretical Computer Science
Groverian Entanglement Measure and Evolution of Entanglement in Search Algorithm for n(= 3, 5)-Qubit Systems with Real Coefficients

Quantum Information Processing
Quantum advantage without entanglement

Quantum Information & Computation

Quantified Score

Hi-index	0.00

Visualization

Abstract

We investigate the issue of speed-up and the necessity of entanglement in Grover's quantum search algorithm. We find that in a pure state implementation of Grover's algorithm entanglement is present even though the initial and target states are product states. In pseudo-pure state implementations, the separability of the states involved defines an entanglement boundary in terms of a bound on the purity parameter. Using this bound we investigate the necessity of entanglement in quantum searching for these pseudopure state implementations. If every active molecule involved in the ensemble is 'charged for' then in existing machines speed-up without entanglement is not possible.