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arXiv · 1107.5545

Entanglement-assisted tomography of a quantum target

A. De Pasquale·P. Facchi·V. Giovannetti·K. Yuasa
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Abstract

We study the efficiency of quantum tomographic reconstruction where the system under investigation (quantum target) is indirectly monitored by looking at the state of a quantum probe that has been scattered off the target. In particular we focus on the state tomography of a qubit through a one-dimensional scattering of a probe qubit, with a Heisenberg-type interaction. Via direct evaluation of the associated quantum Cram\'{e}r-Rao bounds, we compare the accuracy efficiency that one can get by adopting entanglement-assisted strategies with that achievable when entanglement resources are not available. Even though sub-shot noise accuracy levels are not attainable, we show that quantum correlations play a significant role in the estimation. A comparison with the accuracy levels obtainable by direct estimation (not through a probe) of the quantum target is also performed.

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A. De Pasquale, P. Facchi, V. Giovannetti, K. Yuasa. 2011-07-27. Entanglement-assisted tomography of a quantum target. https://doi.org/10.1088/1751-8113/45/10/105309

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