Elucidating Dark Energy with Future 21 cm Observations at the Epoch of   Reionization
  We investigate how precisely we can determine the nature of dark energy such as the equation of state (EoS) and its time dependence by using future observations of 21 cm fluctuations at the epoch of reionization (6.8 <~ z <~ 10) such as Square Kilometre Array (SKA) and Omniscope in combination with those from cosmic microwave background, baryon acoustic oscillation, type Ia supernovae and direct measurement of the Hubble constant. We consider several parametrizations for the EoS and find that future 21 cm observations will be powerful in constraining models of dark energy, especially when its EoS varies at high redshifts. 
Kazunori Kohri, Yoshihiko Oyama, Toyokazu Sekiguchi and Tomo Takahashi
astro-ph.CO hep-ph