Huge density-dependent blueshift of indirect excitons in biased coupled quantum wells

We measure a dynamical blueshift of the indirect exciton in GaAs-coupled quantum wells of over 20 meV for carrier densities in the range ${10}^9–{10}^{12}{\mathrm{cm}}^{-2}.$ We show that this shift is a many-body effect, which is proportional to the indirect exciton density over a broad range of densities, and it is accompanied by homogeneous broadening, which is proportional to the indirect exciton density.