Eur. Phys. J. Plus (2018) 133: 55
https://doi.org/10.1140/epjp/i2018-11883-5

Regular Article

Exploring the gauge/gravity duality of a generalized von Neumann entropy

¹ Departamento de Física, División de Ciencias e Ingenierıas, Campus León, Universidad de Guanajuato, Loma del Bosque 103, CP 37150, León, Guanajuato, Mexico
² Mandelstam Institute for Theoretical Physics, School of Physics, and National Institute for Theoretical Physics, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa

^* e-mail: nana@fisica.ugto.mx

Received: 1 November 2017
Accepted: 17 January 2018
Published online: 14 February 2018

Abstract

We consider a generalized von Neumann entropy that depends only on the density matrix. This is based on a modification of Boltzmann-Gibbs entropy by considering non-equilibrium systems on stationary states, and an entropy functional depending only on the probability. We propose a generalization of the replica trick and find that the resulting modified von Neumann entropy is precisely the previously mentioned entropy that was obtained by other assumptions. Then, we address the question whether alternative entanglement entropies can play a role in the gauge/gravity duality. Our focus are 2d CFT and their gravity duals. Our results show corrections to the von Neumann entropy S₀. If the central charge is small/large they are correspondingly larger/smaller than the usual UV ones and also than the corrections to the corresponding minimal length in AdS₃, which are comparable to the UV ones. This agrees with previous results indicating that the generalized entropy is more relevant for systems with fewer degrees of freedom. The correction terms due to the new entropy would modify the Ryu-Takayanagi identification between the CFT and the gravitational AdS₃ minimal length. We discuss the ingredients for computing the corresponding gravity duals of generalized entanglement entropies.