Towards the nonlinear regime in extensions to GR: assessing possible options. (1st April 2019)

• Record Type: Journal Article
• Authors: Allwright, Gwyneth; Lehner, Luis
• Is Part Of: Classical and quantum gravity. Volume 36:Number 8(2019:Apr.)
• Publication Date: 2019-04-01
• Subjects: gravity -- alternatives to GR -- EFT; Quantum gravity -- Periodicals; Gravitation -- Periodicals; Relativity (Physics) -- Periodicals; Space and time -- Periodicals; Periodicals; 521.1
• DOI: 10.1088/1361-6382/ab0ee1
• Languages: English
• ISSNs: 0264-9381

Abstract

Abstract: Testing general relativity and exploring possible departures has received further input with the possibility to do so through gravitational waves emitted in strongly gravitating/highly dynamical scenarios and also through the availability of exquisitely sensitive cosmological observations. However, most extensions suffer from severe pathologies at the mathematical level which have stymied a thorough exploration of putative theories. With the aid of a model problem which captures typical pathologies, we explore suggested methods to control them. We find that the approach that modifies the equations to control higher-order gradients is both robust and efficient.