Anomalous josephson effect between even- and odd-frequency superconductors

We demonstrate that, contrary to standard wisdom, the lowest-order Josephson coupling is possible between odd- and even-frequency superconductors. The origin of this effect is the induced odd- (even-)frequency pairing component at the interface of bulk even- (odd-)frequency superconductors. The resulting current-phase relation is found to be proportional to cos phi, where phi is the macroscopic phase difference between the two superconductors.