The cosmological constant is probably still zero

Liu, Yang; Padilla, Antonio; Pedro, Francisco G.

Abstract

We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quantised in units of the membrane charges, generically generates a landscape of vacua with a range of values for the cosmological constant that is scanned through membrane nucleation. We list various ways in which the landscape can be made sufficiently dense to be compatible with observations of the current vacuum without running into the empty universe problem. Further, we establish the general criteria required to ensure the absolute stability of the Minkowski vacuum under membrane nucleation and the longevity of those vacua that are parametrically close by. This selects the current vacuum on probabilistic grounds and can even be applied in the classic model of Bousso and Polchinski, albeit with some mild violation of the membrane weak gravity conjecture. We present other models where the membrane weak gravity conjecture is not violated but where the same probabilistic methods can be used to tackle the cosmological constant problem.

• Journal Article Type: Article
• Acceptance Date: Jul 26, 2023
• Online Publication Date: Oct 3, 2023
• Publication Date: Oct 3, 2023
• Deposit Date: Nov 22, 2023
• Publicly Available Date: Nov 22, 2023
• Journal: Journal of High Energy Physics
• Electronic ISSN: 1029-8479
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 2023
• Issue: 10
• Article Number: 14
• DOI: https://doi.org/10.1007/JHEP10%282023%29014
• Keywords: Cosmological models, String and brane phenomenology
• Public URL: https://nottingham-repository.worktribe.com/output/27591770
• Publisher URL: https://link.springer.com/article/10.1007/JHEP10(2023)014
• Additional Information: Received: 28 April 2023; Accepted: 26 July 2023; First Online: 3 October 2023