Extended paraconductivity regime in underdoped cuprates

We reconsider transport experiments in strongly anisotropic high-T-c superconducting cuprates and we find that the universal Aslamazov-Larkin paraconductivity in two dimensions is surprisingly robust, even in the underdoped regime below the pseudogap crossover temperature T (*). We also establish that the underlying normal-state resistivity in the pseudogap region is (almost) linear in temperature, with all the deviations being quantitatively accounted for by Aslamazov-Larkin paraconductivity. The disappearance of paraconductivity is ruled by the suppression of Gaussian pair fluctuations at an energy scale related to T (*).