Quantum-gate characterization in an extended Hilbert space

Peter P. Rohde*, G. J. Pryde, J. L. O'Brien, Timothy C. Ralph

*Corresponding author for this work

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We describe an approach for characterizing the process performed by a quantum gate using quantum process tomography, by first modeling the gate in an extended Hilbert space, which includes nonqubit degrees of freedom. To prevent unphysical processes from being predicted, present quantum process tomography procedures incorporate mathematical constraints, which make no assumptions as to the actual physical nature of the system being described. By contrast, the procedure presented here assumes a particular class of physical processes, and enforces physicality by fitting the data to this model. This allows quantum process tomography to be performed using a smaller experimental data set, and produces parameters with a direct physical interpretation. The approach is demonstrated by example of mode matching in an all-optical controlled-NOT gate. The techniques described are general and could be applied to other optical circuits or quantum computing architectures.

Original languageEnglish
Article number032306
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume72
Issue number3
DOIs
Publication statusPublished - Sep 2005

Bibliographical note

A publisher's note for this article can be found at Phys. Rev. A 72, 039906, https://doi.org/10.1103/PhysRevA.72.039906

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