Studies in dynamical AdS/CFT with modified boundary conditions

Abstract

This thesis investigates the dynamics of Einstein gravity coupled to a scalar field in anti-de Sitter (AdS) spacetime, focusing on the implications of different time-dependent boundary conditions. Two models of the scalar field are used. The first is a massless field that exhibits normalizable linearized normal modes with Dirichlet boundary conditions dual to the standard quantization, as well as other non-normalizable modes. In this model, time-periodic boundary conditions (driving) are applied. The behaviour of the system is investigated for frequencies around the resonances by means of different protocols that modulate both the amplitude and the frequency of the driving. Single-frequency and multiple-frequency drivings are used. The second model corresponds to a field with a mass in the range known as the dual quantization window. This model supports both boundary conditions dual to the standard and the alternative quantizations, as well as mixed boundary conditions, also known in the literature as designer gravity. These mixed boundary conditions are dual to multi-trace deformations of the dual CFT. The nonlinear stability of the system is studied for relevant, marginal and irrelevant deformations.