Using a Floquet boost trnsformation, I show that the non linear photoconductivity can be used to to probe collective charge modes in clean Fractional Qauntum Hall systems. Incompressible phases, irradiated at slightly above the magneto-roton gap, are predicted to exhibit negative photoconductivity and zero resistance states with spontaneous internal electric fields. Non linear conductivity can probe composite fermions' charge excitations in compressible filling factors.
Reference: arXiv:1612.06372 | 
