Linking the Baum-Hawking-Coleman mechanism with unimodular gravity and Vilenkin's probability flux. Issue 8 (16th August 2021)

• Record Type: Journal Article
• Authors: Page, James; Magueijo, João
• Is Part Of: Journal of cosmology and astroparticle physics. Volume 2021:Issue 8(2021)
• Publication Date: 2021-08-16
• Subjects: modified gravity -- quantum cosmology -- dark energy theory -- gravity; Cosmology -- Periodicals; Astrophysics -- Periodicals; 523.0105
• DOI: 10.1088/1475-7516/2021/08/034
• Languages: English
• ISSNs: 1475-7516

Abstract

Abstract: We revisit a mechanism proposed by Hawking to resolve the cosmological constant problem (and the controversy it generated) to identify possibly more palatable alternatives and explore new connections and interpretations. In particular, through the introduction of a new action coupling the four-form field strength F = dA to the cosmological constant via a dynamical field λ( x ), a novel Baum-Hawking-Coleman type mechanism is presented. This mechanism can be seen as a generalisation of Unimodular Gravity. A theory with a similar coupling to " F 2 " is also presented, with promising results. We show how in such theories the 3-form is closely related to the Chern-Simons density, and its associated definition of time. On the interpretational front, we propose a method avoiding the standard Euclidean action prescription, which makes use of Vilenkin's probability flux.