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arXiv · 1504.02460

Power of One Bit of Quantum Information in Quantum Metrology

Hugo Cable·Mile Gu·Kavan Modi
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Abstract

We construct a model of quantum metrology inspired by the computational model known as deterministic quantum computation with one quantum bit (DQC1). Using only one pure qubit together with $l$ fully-mixed qubits we obtain measurement precision at the standard quantum limit, which is typically obtained using the same number of uncorrelated qubits in fully-pure states. The standard quantum limit can be exceeded using an additional qubit, which adds only a small amount of purity. We show that the discord in the final state vanishes only in the limit of attaining infinite precision for the parameter being estimated.

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Hugo Cable, Mile Gu, Kavan Modi. 2015-04-09. Power of One Bit of Quantum Information in Quantum Metrology. https://doi.org/10.1103/physreva.93.040304

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