phase lasts slightly longer than the minimal period it has to last in order to solve the horizon and flatness problems of Standard Big Bang Cosmology).

A key question is to whether the predictions for cosmological perturbations at late times in the expanding phase are sensitive to the details of the bounce phase. For simple parametrizations of the bounce phase, detailed studies have shown that the spectral shape does not change during the bounce phase provided that the duration of the bounce phase is shorter than the length scale of the fluctuations at the bounce point (see, e.g., Ref. [@matterBounce-2] in the case of matter-driven bounces, Ref. [@HLflucts] in the case of the Horava-Lifshitz bounce, Ref. [@Elisa] in the case of the AdS/CFT bounce, and Ref. [@Subodh] for the S-brane bounce). On the other hand, there are examples where the bounce phase yields dramatic changes in the spectrum [@BXue]. The reason why such dramatic changes are possible is that the Hubble radius at the bounce point is infinite, and we cannot invoke the freezing of cosmological perturbations on super-Hubble scales to argue for a constancy of the spectrum[^1].

To further analyze the sensitivity of the spectrum of cosmological fluctuations on 