A thawing tachyon as physical dark energy after DESI DR2: imaginary mass, ghost-free dynamics and a non-crossing prediction
Year: 2026
Type: preprint
Abstract: We test the rolling tachyon of string theory as the physical origin of the evolving dark energy suggested by DESI DR2. The tachyon obeys the null energy condition identically (w ≥ −1), has a Hamiltonian bounded below, and thaws from a Hubble-frozen state into the quadrant w₀ > −1, wₐ < 0 preferred by DESI. Thawing tachyons follow wₐ ≈ −(1.2–1.5)(1+w₀) and reduce distance residuals relative to the best-fitting CPL histories by 22–31% compared with ΛCDM. The model predicts that no reconstruction of w(z) will show a significant excursion below w = −1.
Author: Georgiou, Harley
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225758325
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