Detecting quantum many-body states with imperfect measuring devices
- URL: http://arxiv.org/abs/2512.08150v1
- Date: Tue, 09 Dec 2025 01:06:44 GMT
- Title: Detecting quantum many-body states with imperfect measuring devices
- Authors: K. Uriostegui, C. Pineda, C. Chryssomalakos, V. Rascón Barajas, I. Vázquez Mota,
- Abstract summary: We study a coarse-graining map arising from incomplete and imperfect addressing of particles in a multipartite quantum system.<n>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.
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- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: 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.
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