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arXiv · 0708.1089

Quantum criticality as a resource for quantum estimation

Paolo Zanardi·Matteo G A Paris·Lorenzo Campos Venuti
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Abstract

We address quantum critical systems as a resource in quantum estimation and derive the ultimate quantum limits to the precision of any estimator of the coupling parameters. In particular, if L denotes the size of a system and λis the relevant coupling parameters driving a quantum phase transition, we show that a precision improvement of order 1/L may be achieved in the estimation of λat the critical point compared to the non-critical case. We show that analogue results hold for temperature estimation in classical phase transitions. Results are illustrated by means of a specific example involving a fermion tight-binding model with pair creation (BCS model).

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Paolo Zanardi, Matteo G A Paris, Lorenzo Campos Venuti. 2008-08-01. Quantum criticality as a resource for quantum estimation. https://doi.org/10.1103/physreva.78.042105

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