An Improved Sample Complexity Lower Bound for (Fidelity) Quantum State Tomography

Abstract

We show that $\Omega (rd/\epsilon )$ copies of an unknown rank-$r$, dimension-$d$ quantum mixed state are necessary in order to learn a classical description with $1-\epsilon$ fidelity. This improves upon the tomography lower bounds obtained by Haah, et al. and Wright (when closeness is measured with respect to the fidelity function).

3 pages. Comments welcome

References in corpus (1)

• Coding Theorem and Strong Converse for Quantum Channels

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