We propose here an experiment aimed to determine whether there are superconducting pairing fluctuations in the pseudogap regime of the high-Tc materials. In the experimental setup, two samples above Tc are brought into contact at a single point and the differential AC conductivity in the presence of a constant applied bias voltage between the samples, V, should be measured. We argue the the pairing fluctuations will produce randomly fluctuating Josephson current with zero mean, however the current-current correlator will have a characteristic frequency given by Josephson frequency ωJ=2eV/ℏ. We predict that the differential AC conductivity should have a peak at the Josephson frequency with the width determined by the phase fluctuations time.
@article{arxiv.cond-mat/0002043,
title = {Probing Pseudogap by Josephson Tunneling},
author = {Ivar Martin and Alexander Balatsky},
journal= {arXiv preprint arXiv:cond-mat/0002043},
year = {2009}
}