Redistribution of phase fluctuations in a periodically driven cuprate superconductor

We study the thermally fluctuating state of a bi-layer cuprate superconductor under the periodic action of a staggered field oscillating at optical frequencies. This analysis distills essential elements of the recently discovered phenomenon of light enhanced coherence in YBCO, which was achieved by periodically driving infrared active apical oxygen distortions. The effect of a staggered periodic perturbation is studied using a Langevin description of driven, coupled Josephson junctions, which represent two neighboring pairs of layers and their two plasmons. We demonstrate that the external driving leads to a suppression of phase fluctuations of the low-energy plasmon, an effect which is amplified via the resonance of the high energy plasmon, with a striking suppression of the low-energy fluctuations, as visible in the power spectrum. We also find that this effect acts onto the in-plane fluctuations, which are reduced on long length scales and we discuss the behavior of vortices in the ab-planes and across the weakly coupled junctions.