Catch-Me-If-You-Can: The Overshoot Problem and the Weak/Inflation Hierarchy

Abstract

We study the overshoot problem in the context of post-inflationary string cosmology (in particular LVS). LVS cosmology features a long kination epoch as the volume modulus rolls down the exponential slope towards the final minimum, with an energy density that scales as $m_s^4$. This roll admits attractor tracker solutions, and if these are located the overshoot problem is solved. We show that, provided a sufficiently large hierarchy exists between the inflationary scale and the weak scale, this will always occur in LVS as initial seed radiation grows into the tracker solution. The consistency requirement of ending in a stable vacuum containing the weak hierarchy therefore gives a preference for high inflationary scales -- an anthropic argument, if one likes, for a large inflation/weak hierarchy. We discuss various origins, both universal and model-dependent, of the initial seed radiation (or matter). One particularly interesting case is that of a fundamental string network arising from brane inflation -- this may lead to an early epoch in which the universe energy density principally consists of gravitational waves, while an LVS fundamental string network survives into the present universe.

Added references, corrected typos and improved discussion on the validity of the EFT approach. Matches published version

References in corpus (10)

• Cosmology and the Fate of Dilatation Symmetry
• On the Geometry of the String Landscape and the Swampland
• Monodromy in the CMB: Gravity Waves and String Inflation
• Black Hole Bound on the Number of Species and Quantum Gravity at LHC
• SUSY Breaking in Local String/F-Theory Models
• Dark Radiation in LARGE Volume Models
• Volume Modulus Inflation and the Gravitino Mass Problem
• Testing String Theory with CMB
• Cosmic Strings
• Axions in String Theory $-$ Slaying the Hydra of Dark Radiation

Cited by in corpus (13)

• Testing BSM Physics with Gravitational Waves
• Back to the origins of brane-antibrane inflation
• Cosmic (super)strings with a time-varying tension
• String Thermodynamics In and Out of Equilibrium: Boltzmann Equations and Random Walks
• How an era of kination impacts substructure and the dark matter annihilation rate
• Dark energy with the help of interacting dark sectors
• A universal bound on the duration of a kination era
• Asymptotic bound on slow-roll parameter in stringy quintessence model
• Cosmic superstrings in large volume compactifications: PTAs, LISA and time-varying tension
• Asymptotic behavior of saxion-axion system in stringy quintessence model
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• Curvature-Assisted Dynamical Compactification in a Pre-Inflationary Higher-Dimensional Universe
• Background instability of quintessence model in light of entropy and distance conjecture