2005/02/07 by J. P. Keating, Jonathan P. Keating, Francesco Mezzadri +1 · 15 citations
Computer Science · Mathematics · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum many-body systems #math-ph #math.MP #quant-ph
paper · pdf · doi:10.1103/physrevlett.94.050501
published as Phys.Rev.Lett. 94 (2005) 050501 · 4 pages
openalex publication_date 2005/02/07 · arxiv created 2005/04/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We compute the entropy of entanglement between the first N spins and the rest of the system in the ground states of a general class of quantum spin chains. We show that under certain conditions the entropy can be expressed in terms of averages over ensembles of random matrices. These averages can be evaluated, allowing us to prove that at critical points the entropy grows like \ensuremathκlog2N+\stackrel\texttildelow\ensuremathκ as N\ensuremath→\ensuremath∞, where \ensuremathκ and \stackrel\texttildelow\ensuremathκ are determined explicitly. In an important class of systems, \ensuremathκ is equal to one-third of the central charge of an associated Virasoro algebra. Our expression for \ensuremathκ therefore provides an explicit formula for the central charge.