Prospects for measuring dark energy with 21 cm intensity mapping experiments

Using the 21 cm intensity mapping (IM) technique can efficiently perform large-scale neutral hydrogen surveys, and this method has great potential for measuring dark-energy parameters. Some IM experiments aiming at dark energy in redshift range of $0<z<3$ have been proposed performed, which typical ones using single-dish mode include e.g., BINGO, FAST, SKA1-MID, those interferometric HIRAX, CHIME, Tianlai. In work, we make a forecast these on their capability parameters energy. We find that interferometers advantages constraining cosmological particular, Tianlai cylinder array alone achieve standard precision cosmology $\Lambda$CDM model (i.e., is better than 1%). However, dynamical energy, SKA1-MID performs very well. show simulated data break parameter degeneracies inherent CMB data, CMB+SKA1-MID offers $\sigma(w)=0.013$ $w$CDM model, $\sigma(w_0)=0.080$ $\sigma(w_a)=0.25$ CPL model. Compared with CMB+BAO+SN, provide tighter constraints $w$CDM, but looser (tighter CMB+BAO) CPL, combination CMB+BAO+SN+Tianlai gives $\sigma(w)=0.013$, $\sigma(w_0)=0.055$, $\sigma(w_a)=0.13$. addition, it found synergy FAST ($0<z<0.35$)+SKA1-MID ($0.35<z<0.77$)+Tianlai ($0.77<z<2.55$) promising survey strategy. Finally, residual foreground contamination amplitude considerable impact constraint results. future will powerful probe exploring nature