2008/03/31 by Ferenc Iglói, Ferenc Igloi, Yu-Cheng Lin
Computer Science · Physics and Astronomy · #Ising model #Joint quantum entropy #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum discord #Quantum entanglement #Quantum many-body systems #Quantum phase transition #Quantum relative entropy #Scaling #Spins #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1088/1742-5468/2008/06/p06004
published as J. Stat. Mech. P06004 (2008) · 17 pages, 5 figures, v2: references added+updated
openalex publication_date 2008/06/03 · arxiv created 2008/06/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using free-fermionic techniques we study the entanglement entropy of a block of contiguous spins in a large finite quantum Ising chain in a transverse field, with couplings of different types: homogeneous, periodically modulated and random. We carry out a systematic study of finite-size effects at the quantum critical point, and evaluate subleading corrections both for open and for periodic boundary conditions. For a block corresponding to a half of a finite chain, the position of the maximum of the entropy as a function of the control parameter (e.g. the transverse field) can define the effective critical point in the finite sample. On the basis of homogeneous chains, we demonstrate that the scaling behavior of the entropy near the quantum phase transition is in agreement with the universality hypothesis, and calculate the shift of the effective critical point, which has different scaling behaviors for open and for periodic boundary conditions.