Universal local operator quenches and entanglement entropy

• Main Authors: Arpan Bhattacharyya, Tadashi Takayanagi, Koji Umemoto
• Format: Article
• Language: English
• Published: SpringerOpen 2019-11-01
• Series: Journal of High Energy Physics
• Subjects: AdS-CFT Correspondence; Conformal Field Theory; Black Holes
• Online Access: http://link.springer.com/article/10.1007/JHEP11(2019)107

Abstract We present a new class of local quenches described by mixed states, parameterized universally by two parameters. We compute the evolutions of entanglement entropy for both a holographic and Dirac fermion CFT in two dimensions. This turns out to be equivalent to calculations of two point functions on a torus. We find that in holographic CFTs, the results coincide with the known results of pure state local operator quenches. On the other hand, we obtain new behaviors in the Dirac fermion CFT, which are missing in the pure state counterpart. By combining our results with the inequalities known for von-Neumann entropy, we obtain an upper bound of the pure state local operator quenches in the Dirac fermion CFT. We also explore predictions about the behaviors of entanglement entropy for more general mixed states.