{"paper":{"title":"Bounds on the entanglement entropy by the number entropy in non-interacting fermionic systems","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["cond-mat.quant-gas","cond-mat.stat-mech","cond-mat.str-el"],"primary_cat":"cond-mat.dis-nn","authors_text":"2), (2) Department of Physics, Astronomy, Canada), Germany, Jesko Sirker (2), Kaiserslautern, Maximilian Kiefer-Emmanouilidis (1, Michael Fleischhauer (1) ((1) Department of Physics, Razmik Unanyan (1), Research Center OPTIMAS, University of Kaiserslautern, University of Manitoba, Winnipeg","submitted_at":"2020-03-06T10:04:16Z","abstract_excerpt":"Entanglement in a pure state of a many-body system can be characterized by the R\\'enyi entropies $S^{(\\alpha)}=\\ln\\textrm{tr}(\\rho^\\alpha)/(1-\\alpha)$ of the reduced density matrix $\\rho$ of a subsystem. These entropies are, however, difficult to access experimentally and can typically be determined for small systems only. Here we show that for free fermionic systems in a Gaussian state and with particle number conservation, $\\ln S^{(2)}$ can be tightly bound by the much easier accessible R\\'enyi number entropy $S^{(2)}_N=-\\ln \\sum_n p^2(n)$ which is a function of the probability distribution "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2003.03112","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2003.03112/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}