Sep 15 – 18, 2014
Dept. of Physics and Astronomy
Europe/Rome timezone

Excited state entanglement in conformal field theory: extensivity and the role of microscopic detail

Sep 17, 2014, 4:30 PM
Aula Magna (Dept. of Physics and Astronomy)

Aula Magna

Dept. of Physics and Astronomy

A. Righi Building Via Irnerio 46, 40126 Bologna (Italy)


Tamas Palmai (SISSA, INFN TS)


We study the excited state subsystem purity (equivalent to 2nd Renyi entropy) as a measure of entanglement in 1+1d conformal field theories. In order to access the highly excited states we generalize the replica approach and develop a systematic framework to treat arbitrary states (in particular descendants) by means of novel CFT techniques including transformation of descendant fields under conformal mappings and exact evaluation of descendant n-point functions. By examining a number of individual states in the critical Ising and three-state Potts models we uncover a new interesting regime of the subsystem purity as a function of the relative subsystem size: when the subsystems are comparable purity decays exponentially with an exponent depending only on the excitation energy and in a nonlinear way. For the Renyi entropy this translates as a quasi thermodynamic entropy, that is extensive but obeys a nonlinear 1st law analog. As an additional application of the present framework we show preliminary results for ground and excited state Renyi entropies in the massive Ising model using a truncated conformal space approach. arXiv:1406.3182 [hep-th]

Primary author

Tamas Palmai (SISSA, INFN TS)

Presentation materials

There are no materials yet.