Activating hidden metrological usefulness
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.
Cite
@article{arxiv.1911.02592,
title = {Activating hidden metrological usefulness},
author = {Géza Tóth and Tamás Vértesi and Paweł Horodecki and Ryszard Horodecki},
journal= {arXiv preprint arXiv:1911.02592},
year = {2021}
}
Comments
7 pages including 1 figure + 12-page supplement including 3 figures, revtex4.2; v2:published version