TY - JOUR
T1 - Quantum-gate characterization in an extended Hilbert space
AU - Rohde, Peter P.
AU - Pryde, G. J.
AU - O'Brien, J. L.
AU - Ralph, Timothy C.
N1 - A publisher's note for this article can be found at Phys. Rev. A 72, 039906, https://doi.org/10.1103/PhysRevA.72.039906
PY - 2005/9
Y1 - 2005/9
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=28844436835&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/record.url?scp=28844457564&partnerID=8YFLogxK
UR - https://doi.org/10.1103/PhysRevA.72.039906
U2 - 10.1103/PhysRevA.72.032306
DO - 10.1103/PhysRevA.72.032306
M3 - Article
AN - SCOPUS:28844436835
VL - 72
JO - Physical Review A: covering atomic, molecular, and optical physics and quantum information
JF - Physical Review A: covering atomic, molecular, and optical physics and quantum information
SN - 2469-9926
IS - 3
M1 - 032306
ER -