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arXiv · 1806.06697

Loop State-preparation-and-measurement tomography of a two-qubit system

M. E. Feldman·G. K. Juul·S. J. Van Enk·M. Beck
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Abstract

We experimentally demonstrate that loop state-preparation-and-measurement (SPAM) tomography is capable of detecting correlated errors in a two-qubit system. We prepare photon pairs in a state that approximates a Werner state, which may or may not be entangled. By performing measurements with multiple different detector settings we are able to detect correlated errors between two single-qubit measurements performed in different locations. No assumptions are made concerning either the state preparations or the measurements, other than that the dimensions of the states and the positive-operator-valued measures describing the detectors are known. The only other needed information is experimentally measured expectation values, which are analyzed for self-consistency. This demonstrates that loop SPAM tomography is a useful technique for detecting errors that would degrade the performance of multiple-qubit quantum information processors.

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M. E. Feldman, G. K. Juul, S. J. Van Enk, M. Beck. 2018-06-14. Loop State-preparation-and-measurement tomography of a two-qubit system. https://doi.org/10.1364/josab.35.001811

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