Cosmological constraints on string scale and coupling arising from tachyonic instability

2005/02/28 by Kari Enqvist, Asko Jokinen, Anupam Mazumdar +4 · 3 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #hep-ph #hep-th

paper · pdf · doi:10.1088/1126-6708/2005/08/084

published as JHEP 0508 (2005) 084 · 12 pages, 2 figures, typo corrected, discussion and references added

arxiv created 2005/03/18 · openalex publication_date 2005/08/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We demonstrate that string motivated inflation ending via tachyonic instability leaves a detectable imprint on the cosmic microwave background (CMB) radiation by virtue of the excitation of non-Gaussian gravitational fluctuations. The present WMAP bound on non-Gaussianity is shown to constrain the string scale by M_S/M_P≤ 10^-4 for string coupling g_s<0.1, hence improving the existing bounds. If tachyon fluctuations during inflation are not negligible, we find the stringent constraint g_s∼ 10^-9 for M_S/M_P<10^-3. This case may soon be ruled out by the forthcoming CMB non-Gaussinianity bounds.

Citations

• Remarks on Tachyon Condensation in Superstring Field Theory
• Non-Gaussianity from Inflation: Theory and Observations
• Field Theory of Tachyon Matter
• de Sitter Vacua in String Theory
• Non-Gaussianity from instant and tachyonic preheating

Cited by

• Non-Gaussianity from tachyonic preheating in hybrid inflation
• Predictions for non-Gaussianity from non-local inflation
• Reheating in supersymmetric high scale inflation

Related

• Consistency of cosmic strings with cosmic microwave background measurements
• Measuring CMB non-Gaussianity as a probe of Inflation and Cosmic Strings
• Constraints on brane inflation from WMAP3
• Non-Gaussianity from instant and tachyonic preheating
• Some inequalities bridging stringy parameters and cosmological observables