Activation of metrologically useful genuine multipartite entanglement
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arXiv
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2022
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| _version_ | 1866909130661298176 |
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| author | Trényi, Róbert Lukács, Árpád Horodecki, Paweł Horodecki, Ryszard Vértesi, Tamás Tóth, Géza |
| author_facet | Trényi, Róbert Lukács, Árpád Horodecki, Paweł Horodecki, Ryszard Vértesi, Tamás Tóth, Géza |
| contents | We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of large number of copies, even if the state is weakly entangled and not even more useful than separable states. This way we activate metrologically useful genuine multipartite entanglement. Remarkably, not only that the maximally achievable metrological usefulness is attained exponentially fast in the number of copies, but it can be achieved by the measurement of few simple correlation observables. We also make general statements about the usefulness of a single copy of pure entangled states. We surprisingly find that the multiqubit states presented in Hyllus et al. [Phys. Rev. A 82, 012337 (2010)], which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and its possible use for quantum metrology in a noisy environment. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2203_05538 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Activation of metrologically useful genuine multipartite entanglement Trényi, Róbert Lukács, Árpád Horodecki, Paweł Horodecki, Ryszard Vértesi, Tamás Tóth, Géza Quantum Physics We consider quantum metrology with several copies of bipartite and multipartite quantum states. We characterize the metrological usefulness by determining how much the state outperforms separable states. We identify a large class of entangled states that become maximally useful for metrology in the limit of large number of copies, even if the state is weakly entangled and not even more useful than separable states. This way we activate metrologically useful genuine multipartite entanglement. Remarkably, not only that the maximally achievable metrological usefulness is attained exponentially fast in the number of copies, but it can be achieved by the measurement of few simple correlation observables. We also make general statements about the usefulness of a single copy of pure entangled states. We surprisingly find that the multiqubit states presented in Hyllus et al. [Phys. Rev. A 82, 012337 (2010)], which are not useful, become useful if we embed the qubits locally in qutrits. We discuss the relation of our scheme to error correction, and its possible use for quantum metrology in a noisy environment. |
| title | Activation of metrologically useful genuine multipartite entanglement |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2203.05538 |