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Activating Hidden Metrological Usefulness. | LitMetric

Activating Hidden Metrological Usefulness.

Phys Rev Lett

International Centre for Theory of Quantum Technologies, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland and Institute of Theoretical Physics and Astrophysics, National Quantum Information Centre, Faculty of Mathematics, Physics and Informatics, University of Gdańsk, Wita Stwosza 57,80-308 Gdańsk, Poland.

Published: July 2020

AI Article Synopsis

Article Abstract

We consider bipartite entangled states that cannot outperform separable states in any linear interferometer. Then, we show that these states can still be more useful metrologically than separable states if several copies of the state are provided or an ancilla is added to the quantum system. We present a general method to find the local Hamiltonian for which a given quantum state performs the best compared to separable states. We obtain analytically the optimal Hamiltonian for some quantum states with a high symmetry. We show that all bipartite entangled pure states outperform separable states in metrology. Some potential applications of the results are also suggested.

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Source
http://dx.doi.org/10.1103/PhysRevLett.125.020402DOI Listing

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