N = 2 PNGB quintessence dark energy

Abstract

In this paper, we show that a pseudo-Nambu–Goldstone boson (PNGB) quintessence of spontaneous symmetry breaking (SSB) is responsible for an epoch of late-time cosmic acceleration. We suggest that an N = 2PNGB quintessence with SSB can give rise to the fast-roll cosmic acceleration in the evolution of the Universe. In the N = 2 PNGB quintessence model, the standard slow-roll condition in which the absolute value of the tachyonic mass squared $|m_q^2|$ of this model is much less than the square of the Hubble constant $H^2$, is broken down to the fast-roll condition, $|m_q^2|=O(H^2)$. However, the fast-rolling associated with the N = 2 PNGB quintessence of SSB is shown to lead to the epoch of late-time cosmic acceleration. Indeed, in our PNGB model, this epoch can be quite long-lasting because the mass of the N = 2 PNGB quintessence field is extremely small at $m_q \approx 10^{-33} \mathrm {eV}$.