Evidences for bouncing evolution before inflation in cosmological surveys

Inflationary cosmology with a preceding nonsingular bounce can lead to changes on the primordial density fluctuations. One significant prediction is that the amplitude of the power spectrum may undergo a jump at a critical scale. In this Letter we propose a phenomenological parametrization of the primordial power spectrum in this scenario and confront the jump feature with latest cosmological data. Performing a global fitting, we utilize this possibility to derive a novel method for constraining bounce parameters via cosmological measurements. Combining the CMB, LSS and SNIa data, our result interestingly reveals that a nonsingular bounce, if exists, should be a fast bounce which happens at a very high energy scale, as we get an upper limit on the bounce parameters.