2008/04/07 by V. Popkov, Vladislav Popkov, M. Salerno +1
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Quantum many-body systems #Statistical Mechanics and Entropy #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1209/0295-5075/84/30007
published as Europhys.Lett., 84, 30007 (2008) · 4 pages, 2 figures
arxiv created 2008/04/07 · openalex publication_date 2008/10/28 · arxiv updated 2011/07/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
The spectrum of the reduced density matrix and the temperature dependence of the von Neumann entropy (VNE) are analytically obtained for a system of hard-core bosons on a complete graph which exhibits a phase transition to a Bose-Einstein condensate at T = T c . It is demonstrated that the VNE undergoes a crossover from purely logarithmic at T =0 to purely linear in block size n behaviour for T ⩾ T c . For intermediate temperatures, VNE is a sum of two contributions which are interpreted as the classical (Gibbs) and the quantum (due to entanglement) parts of the von Neumann entropy.