N=2 PNGB Quintessence Dark Energy
  In this paper we show that a pseudo-Nambu-Goldstone boson (PNGB) quintessence
of spontaneous symmetry breaking (SSB) is responsible for an epoch of the late
time cosmic acceleration. We suggest that an N=2 PNGB quintessence with SSB can
give rise to the fast-roll cosmic acceleration in 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, it is shown that the
fast-rolling associated with the N=2 PNGB quintessence of SSB can be led to the
epoch of the late time cosmic acceleration. Indeed, in our PNGB model, this
epoch can be quite long lasting since the mass of the N=2 PNGB quintessence
field is extremely small as $m_q \approx 10^{-33} \rm{eV}$.
