2015/12/31 by M. A. Rajabpour · 1 citation
Physics and Astronomy · #cond-mat.other #cond-mat.str-el #hep-th #quant-ph
paper · pdf · doi:10.1088/1742-5468/2016/06/063109
published as J. Stat. Mech. (2016) 063109 · V2: 20 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1503.07771
arxiv created 2016/04/12 · arxiv updated 2016/08/03
We calculate analytically the Rényi bipartite entanglement entropy Sα of the ground state of 1+1 dimensional conformal field theories (CFT) after performing a projective measurement in a part of the system. We show that the entanglement entropy in this setup is dependent on the central charge and the operator content of the system. When the measurement region A separates the two parts B and B, the entanglement entropy between B and B decreases like a power-law with respect to the characteristic distance between the two regions with an exponent which is dependent on the rank α of the Rényi entanglement entropy and the smallest scaling dimension present in the system. We check our findings by making numerical calculations on the Klein-Gordon field theory (coupled harmonic oscillators) after fixing the position (partial measurement) of some of the oscillators. We also comment on the post-measurement entanglement entropy in the massive quantum field theories.