Speedy Sound and Cosmic Structure

2008/03/31 by João Magueijo, Joao Magueijo · 4 citations
Mathematics · Physics and Astronomy · #Acoustics #Astrophysics #Black Holes and Theoretical Physics #COSMIC cancer database #Classical mechanics #Computer science #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Heuristics #Mathematics #Mechanism (biology) #Physics #Quantum mechanics #Scalar (mathematics) #Speed of sound #Statistical physics #Theoretical physics #Universe #astro-ph #gr-qc #hep-ph

paper · pdf · doi:10.1103/physrevlett.100.231302

published as Phys.Rev.Lett.100:231302,2008 · To be published in Phys. Rev. Letters

arxiv created 2008/06/04 · openalex publication_date 2008/06/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

If the speed of sound were vastly larger in the early Universe, a near scale-invariant spectrum of density fluctuations could have been produced even if the Universe did not submit to conventional solutions to the horizon problem. We examine how the mechanism works, presenting full mathematical solutions and their heuristics. We then discuss several concrete models based on scalar fields and hydrodynamical matter that realize this mechanism, but stress that the proposed mechanism is more fundamental and general.

Citations

• Causality and superluminal behavior in classical field theories: Applications tok-essence theories and modified-Newtonian-dynamics-like theories of gravity
• A new inflationary universe scenario: A possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems
• Cuscuton cosmology: Dark energy meets modified gravity
• New varying speed of light theories
• Enhancing the tensor-to-scalar ratio in simple inflation
• Inflationary Theory and Alternative Cosmology
• k-Essence, superluminal propagation, causality and emergent geometry
• Seeding of primordial perturbations during a decelerated expansion
• Duality invariance of cosmological perturbation spectra
• SUPERLUMINARY UNIVERSE: A POSSIBLE SOLUTION TO THE INITIAL VALUE PROBLEM IN COSMOLOGY
• A time varying speed of light as a solution to cosmological puzzles
• k-Inflation

Cited by

• Horizon-preserving dualities and perturbations in non-canonical scalar field cosmologies
• Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities
• Flow in cyclic cosmology
• Strong coupling problem with time-varying sound speed