{"paper":{"title":"Ground-state entanglement in coupled qubits","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"A.Yu. Smirnov, M.H. Amin","submitted_at":"2013-06-25T16:34:54Z","abstract_excerpt":"We study a system of qubits that are coupled to each other via only one degree of freedom represented, e.g., by $\\sigma_z$-operators. We prove that, if by changing the Hamiltonian parameters, a non-degenerate ground state of the system is continuously transformed in such a way that the expectation values of $\\sigma_z$ operators of at least two coupled qubits change, this ground state is entangled. Using this proof, we discuss connection between energy level anticrossings and ground state entanglement. Following the same line of thought, we introduce entanglement witnesses, based on cross-susce"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1306.6024","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":""},"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"}