Consistency of Tachyacoustic Cosmology with de Sitter Swampland Conjectures

Abstract

Recent studies show that there is tension between the de Sitter swampland conjectures proposed by Obeid, et al. and inflationary cosmology. In this paper, we consider an alternative to inflation, `tachyacoustic' cosmology, in light of swampland conjectures. In tachyacoustic models, primordial perturbations are generated by a period of superluminal sound speed instead of accelerating expansion. We show that realizations of tachyacoustic Lagrangians can be consistent with the de Sitter swampland conjectures, and therefore can in principle be consistent with a UV-complete theory. We derive a general condition for models with $c_S>1$ to be consistent with swampland conjectures.

arXiv comment6 pages, 2 figures (v3: new section added; version accepted by JCAP.)

References in corpus (39)

• The String Landscape, Black Holes and Gravity as the Weakest Force
• Reconstructing the Inflaton Potential --- an Overview
• Warm Inflation
• On the Cosmological Implications of the String Swampland
• k-Essence, superluminal propagation, causality and emergent geometry
• Cuscuton: A Causal Field Theory with an Infinite Speed of Sound
• Inflation: flow, fixed points and observables to arbitrary order in slow roll
• The string swampland constraints require multi-field inflation
• Reconstructing the Inflaton Potential---in Principle and in Practice
• Warm inflation as a way out of the swampland
• The zoo plot meets the swampland: mutual (in)consistency of single-field inflation, string conjectures, and cosmological data
• Cuscuton Cosmology: Dark Energy meets Modified Gravity
• A note on Inflation and the Swampland
• Warm Inflation in the light of Swampland Criteria
• Eternal Inflation and the Refined Swampland Conjecture
• The holographic fluid dual to vacuum Einstein gravity
• A note on Single-field Inflation and the Swampland Criteria
• Eternal Inflation and Swampland Conjectures
• Rescuing Single Field Inflation from the Swampland
• Avoiding the string swampland in single-field inflation: Excited initial states
• Speedy sound and cosmic structure
• Steep Eternal Inflation and the Swampland
• Quantum modes in DBI inflation: exact solutions and constraints from vacuum selection
• Reconstructing a general inflationary action
• Cuscuton Bounce
• Tachyacoustic Cosmology: An Alternative to Inflation
• Type I Hilltop Inflation and the Refined Swampland Criteria
• Chaotic inflation on the brane and the Swampland Criteria
• What does Inflation say about Dark Energy given the Swampland Conjectures?
• The critical geometry of a thermal big bang
• General conditions for scale-invariant perturbations in an expanding universe
• Theory of Cosmological Perturbations with Cuscuton
• de Sitter swampland bound in the Dirac-Born-Infeld inflation model
• A Spinodal Solution to Swampland Inflationary Constraints
• Theoretical implications of detecting gravitational waves
• Horizon-preserving dualities and perturbations in non-canonical scalar field cosmologies
• Can non-local or higher derivative theories provide alternatives to inflation?
• Non-Gaussian signatures of Tachyacoustic Cosmology
• Attractor Solutions in Tachyacoustic Cosmology

Cited by in corpus (7)

• Festina Lente: EFT Constraints from Charged Black Hole Evaporation in de Sitter
• Multi-field Inflation in High-Slope Potentials
• Reheating After Swampland Conjecture
• Non-canonical kinetic structures in the swampland
• Hitchhiker's Guide to the Swampland: The Cosmologist's Handbook to the string-theoretical Swampland Programme
• The Trans-Planckian problem in Tachyacoustic Cosmology
• Inflation from a chaotic potential with a step