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| Main Authors: | , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2512.08150 |
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| _version_ | 1866917444398874624 |
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| author | Uriostegui, K. Pineda, C. Chryssomalakos, C. Barajas, V. Rascón Mota, I. Vázquez |
| author_facet | Uriostegui, K. Pineda, C. Chryssomalakos, C. Barajas, V. Rascón Mota, I. Vázquez |
| contents | We study a coarse-graining map arising from incomplete and imperfect addressing of particles in a multipartite quantum system. In its simplest form, corresponding to a two-qubit state, the resulting channel produces a convex mixture of the two partial traces. We derive the probability density of obtaining a given coarse-grained state, using geometric arguments for two qubits coarse-grained to one, and random-matrix methods for larger systems. As the number of qubits increases, the probability density sharply concentrates around the maximally mixed state, making nearly pure coarse-grained states increasingly unlikely. For two qubits, we also compute the inverse state needed to characterize the effective dynamics under coarse-graining and find that the average preimage of the maximally mixed state contains a finite singlet component. Finally, we validate the analytical predictions by inferring the underlying probabilities from Monte-Carlo-generated coarse-grained statistics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_08150 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Detecting quantum many-body states with imperfect measuring devices Uriostegui, K. Pineda, C. Chryssomalakos, C. Barajas, V. Rascón Mota, I. Vázquez Quantum Physics We study a coarse-graining map arising from incomplete and imperfect addressing of particles in a multipartite quantum system. In its simplest form, corresponding to a two-qubit state, the resulting channel produces a convex mixture of the two partial traces. We derive the probability density of obtaining a given coarse-grained state, using geometric arguments for two qubits coarse-grained to one, and random-matrix methods for larger systems. As the number of qubits increases, the probability density sharply concentrates around the maximally mixed state, making nearly pure coarse-grained states increasingly unlikely. For two qubits, we also compute the inverse state needed to characterize the effective dynamics under coarse-graining and find that the average preimage of the maximally mixed state contains a finite singlet component. Finally, we validate the analytical predictions by inferring the underlying probabilities from Monte-Carlo-generated coarse-grained statistics. |
| title | Detecting quantum many-body states with imperfect measuring devices |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2512.08150 |