Fig. 4

Resonant strong-field ionization yield of ultracold ⁸⁷Rb. a Keldysh parameter γ (blue dashed line) and ionization probabilities P after a single laser pulse obtained by ab-initio time-dependent Schrödinger equation (TDSE) calculations (red solid line). b Measured fraction of lost atoms f_l (blue dots) for laser pulses of 1022 nm wavelength and comparison to the loss fraction \(f_{\mathrm{l}}^{{\mathrm{sim}}}\) resulting from TDSE calculations (red dashed line). The nominal over-the-barrier intensity I_OBI is depicted as vertical black dashed line. The red dotted lines indicate an \(I_0^2\) scaling. Vertical error bars represent the standard deviation of the individual loss measurements. Horizontal error bars consist of the standard deviation of the intensity in the respective bin and include systematic errors in the intensity measurement