Cosmological phase transitions and the swampland

• Published in: The journal of high energy physics 2024-02, Vol.2024 (2), p.114-16, Article 114
• Main Author: Venken, Gerben
• Format: Article
• Language: English
• Subjects: Classical and Quantum Gravitation; Confinement; Cosmology of Theories BSM; de Sitter space; Elementary Particles; Gravitational waves; Heating; Phase transitions; Phase Transitions in the Early Universe; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Scale (ratio); String and Brane Phenomenology; String Theory; Temperature effects
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP02(2024)114

A bstract I consider the Festina Lente Swampland bound and argue taking thermal effects, as for instance occur during reheating, into account significantly strengthens the implications of this bound. I argue that the confinement scale should be higher than a scale proportional to the vacuum energy, while Festina Lente without thermal effects only bounds the confinement scale to be above the Hubble scale. For Higgsing of nonabelian gauge fields, I find that the magnitude of the Higgs mass should be heavier than a bound proportional to the Electroweak scale (or generally the scale set by the Higgs VEV). The measured values of the Higgs in the SM satisfy the bound. A way to avoid the bound being violated during inflation is to have a large number of species becoming light. If one wants the inflationary scale to lie below the species scale in this case, this bounds the inflationary scale to be ≪ 10 5 GeV. These bounds have phenomenological implications for BSM physics such as GUTs, suggesting for example a weak or absent gravitational wave signature from the GUT Higgsing phase transition.