https://doi.org/10.1140/epjp/s13360-022-02529-6
Regular Article
Vacuum decay in quadratic gravity
1
Dipartimento di Fisica, Università di Trento, Via Sommarive 14, 38123, Povo, TN, Italy
2
Trento Institute for Fundamental Physics and Applications (TIFPA)-INFN, Via Sommarive 14, 38123, Povo, TN, Italy
b
massimiliano.rinaldi@unitn.it
Received:
27
November
2021
Accepted:
26
February
2022
Published online:
11
March
2022
Metastable states decay at zero temperature through quantum tunnelling at an exponentially small rate, which depends on the Coleman–de Luccia instanton, also known as bounce. In some theories, the bounce may not exist or its on-shell action may be ill-defined or infinite, thus hindering the vacuum decay process. In this paper, we test this possibility in modified theories of gravity interacting with a real scalar field. We consider an Einstein–Hilbert term with a non-minimally coupled scalar field and a quadratic Ricci scalar contribution. To tackle the problem, we use a new analytic method, with which we prove that the scalar field on the bounce has a universal behaviour at large Euclidean radii, almost independently of the potential. Our main result is that the quadratic Ricci scalar prevents the decay, regardless of the other terms in the action.
The funding note has been missing and added: Open access funding provided by Università degli Studi di Salerno within the CRUI-CARE Agreement.
Copyright comment corrected publication 2022
© The Author(s) 2022. corrected publication 2022
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
