2004/05/11 by N. Canosa, R. Rossignoli
Computer Science · Mathematics · Physics and Astronomy · #Field (mathematics) #Heisenberg limit #Limit (mathematics) #Mathematical analysis #Mathematical physics #Mathematics #Physics #Pure mathematics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum entanglement #Quantum mechanics #Qubit #Statistical physics #Symmetry breaking #Thermal #Thermodynamics #Von Neumann architecture #quant-ph
paper · pdf · doi:10.1103/physreva.69.052306
published as Physical Review A 69, 052306 (2004) · 7 pages, 4 figures
openalex publication_date 2004/05/11 · openalex created_date 2016/06/24 · arxiv created 2016/09/27 · arxiv updated 2016/10/05 · openalex updated_date 2026/08/05
We examine the entanglement of general mixed states of a two-qubit Heisenberg XYZ chain in the presence of a magnetic field, and its detection by means of different criteria. Both the exact separability conditions and the weaker conditions implied by the disorder and the von Neumann entropic criteria are analyzed. The ensuing limit temperatures for entanglement in thermal states of different XYZ models are then examined and compared with the limit temperature of the symmetry-breaking solution in a mean-field-type approximation. The latter, though generally lower, can also be higher than the exact limit temperature for entanglement in certain cases, indicating that symmetry breaking does not necessarily entail entanglement. The reentry of entanglement for increasing temperatures is also discussed.