Cosmological signature of tachyon condensation

Abstract

We consider the dynamics of the open string tachyon condensation in a framework of the cubic fermionic String Field Theory including a non-minimal coupling with closed string massless modes, the graviton and the dilaton. Coupling of the open string tachyon and the dilaton is motivated by the open String Field Theory in a linear dilaton background and the flat space-time. We note that the dilatonic gravity provides several restrictions on the tachyon condensation and show explicitly that the influence of the dilaton on the tachyon condensation is essential and provides a significant effect: oscillations of the Hubble parameter and the state parameter become of a cosmological scale. We give an estimation for the period of these oscillations (0.1-1.0) Gyr and note a good agreement of this period with the observed oscillations with a period (0.15-0.65) Gyr in a distribution of quasar spectra.