Universität Potsdam Institut für Physik KarlLiebknechtStr. 24/25 14476 PotsdamGolm 



AbstractWe establish that the leading critical scaling of the singlecopy entanglement is exactly one half of the entropy of entanglement of a block in critical infinite spin chains in a general setting, using methods of conformal field theory. Conformal symmetry imposes that the singlecopy entanglement for critical manybody systems scales as E_1(\rho_L)=(c/6) \log L (c/6) (\pi^2/\log L) + O(1/L), where L is the number of constituents in a block of an infinite chain and c corresponds to the central charge. This proves that from a single specimen of a critical chain, already half the entanglement can be distilled compared to the rate that is asymptotically available. The result is substantiated by a quantitative analysis for all translationally invariant quantum spin chains corresponding to general isotropic quasifree fermionic models. An analytic example of the XY model shows that away from criticality the above simple relation is only maintained near the quantum phase transition point. file generated: 18 Apr 2007


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