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Additivity of decoherence measures for multiqubit quantum systems

Leonid Fedichkin·Arkady Fedorov·Vladimir Privman
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Abstract

We introduce new measures of decoherence appropriate for evaluation of quantum computing designs. Environment-induced deviation of a quantum system's evolution from controlled dynamics is quantified by a single numerical measure. This measure is defined as a maximal norm of the density matrix deviation. We establish the property of additivity: in the regime of the onset of decoherence, the sum of the individual qubit error measures provides an estimate of the error for a several-qubit system. This property is illustrated by exact calculations for a spin-boson model.

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Leonid Fedichkin, Arkady Fedorov, Vladimir Privman. 2003-09-29. Additivity of decoherence measures for multiqubit quantum systems. https://doi.org/10.1016/j.physleta.2004.06.021

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