paper

Retrieving maximum information of symmetric states from their corrupted copies

arXiv:2502.10627 · doi:10.1103/PhysRevA.111.022424

Abstract

Using quantum measurements to extract information from states is a matter of routine in quantum science and technologies. A recent work [Phys. Rev. Lett. 133, 040202 (2024)] reported the finding that the symmetric structures of a state can be harnessed to dramatically reduce the sample complexity in extracting information from the state. However, due to the presence of noise, the actual state at hand is often corrupted, making its symmetric structures distorted before the execution of quantum measurements. Here, using the methodology of quantum metrology, we identify the optimal measurement that can retrieve maximum information of a symmetric state from its corrupted copies. We show that this measurement can be found by solving a semidefinite program in generic cases and can be explicitly determined for a large class of noise models covariant under the symmetry group in question. The results of this study nicely complement the recent work by providing a method to optimally utilize the distorted symmetric structures of corrupted states for information retrieval.

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Retrieving maximum information of symmetric states from their corrupted copies · wovepaper