Accelerated expansion of the universe driven by tachyonic matter

2002/04/18 by T. Padmanabhan · 3 citations
Physics and Astronomy · #hep-th #astro-ph #gr-qc

paper · pdf · doi:10.1103/physrevd.66.021301

published as Phys.Rev.D66:021301,2002 · 4 pages; uses revtex4

arxiv created 2002/04/18 · arxiv updated 2009/11/30

Abstract

It is an accepted practice in cosmology to invoke a scalar field with potential V(ϕ) when observed evolution of the universe cannot be reconciled with theoretical prejudices. Since one function-degree-of-freedom in the expansion factor a(t) can be traded off for the function V(ϕ), it is \it always possible to find a scalar field potential which will reproduce a given evolution. I provide a recipe for determining V(ϕ) from a(t) in two cases:(i) Normal scalar field with Lagrangian \cal L = (1/2)∂_aϕ∂^aϕ- V(ϕ) used in quintessence/dark energy models. (ii) A tachyonic field with Lagrangian \cal L = -V(ϕ) [ 1- ∂_aϕ∂^aϕ]^1/2 , motivated by recent string theoretic results. In the latter case, it is possible to have accelerated expansion of the universe during the late phase in certain cases. This suggests a string theory based interpretation of the current phase of the universe with tachyonic condensate acting as effective cosmological constant.

Cited by

• Alleviating the Hubble Tension with Logarithmic Dark Energy: Constraints on the w_logCDM Model
• Stability analysis of dilaton-inspired scalar field within the geometrical trinity of gravity
• Observational Constraints and Geometric Diagnostics of Barboza-Alcaniz and Logarithmic Dark Energy Parametrizations