Authors: Javier M Magán Stefan Vandoren
Publish Date: 2015/07/28
Volume: 2015, Issue: 7, Pages: 150-
Abstract
Entanglement in random states has turned into a useful approach to quantum thermalization and black hole physics In this article we refine and extend the ‘random unitaries framework’ to quantum field theories QFT and to include conserved charges We show that in QFT the connection between typical states reduced subsystems and thermal dynamics is more transparent within the Fock basis We provide generic formulae for the typical reduced density matrices and entanglement entropies of any given subset of particles To illustrate our methods we apply the generic framework to the simplest but non trivial cases a massless scalar field in two dimensions and its generalization to the case of N scalar fields including the large N limit We find the effective temperature by matching the reduced dynamics to a Gibbs ensemble and derive the equation of state of the QFT The deviations from perfect thermality are shown to be of order 1/S instead of exp−S a result which might be relevant for black hole physics Finally we describe the analogue of the socalled ‘Page curve’ in the QFT scenario as a function of the energy scale which divides high from low energy degrees of freedomThis article is published under an open access license Please check the Copyright Information section for details of this license and what reuse is permitted If your intended use exceeds what is permitted by the license or if you are unable to locate the licence and reuse information please contact the Rights and Permissions team
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