TY  - JOUR
A1  - Orus, Roman
A1  - Latorre, Jose Ignacio
A1  - Eisert, Jens
A1  - Cramer, Marcus
T1  - Half the entanglement in critical systems is distillable from a single specimen
N2  - We establish a quantitative relationship between the entanglement content of a single quantum chain at a critical point and the corresponding entropy of entanglement. We find that, surprisingly, the leading critical scaling of the single-copy entanglement with respect to any bipartitioning is exactly one-half of the entropy of entanglement, in a general setting of conformal field theory and quasifree systems. Conformal symmetry imposes that the single-copy entanglement scales as E-1(rho(L))=(c/6)ln L-(c/6)(pi(2)/ln L)+O(1/L), where L is the number of constituents in a block of an infinite chain and c denotes the central charge. This shows 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 all isotropic quasifree fermionic models. An example of the XY spin chain shows that away from criticality the above relation is maintained only near the quantum phase transition
Y1  - 2006
UR  - http://pra.aps.org/
U6  - https://doi.org/10.1103/Physreva.73.060303
ER  -