Some consequences ofscrPscrTsymmetry for optical rotation experiments

We perform a general symmetry analysis of optical experiments on samples in the ``scrPscrT state,'' that is, samples for which 3D inversion symmetry scrP and time inversion symmetry scrT are each broken, but which are invariant under the product scrPscrT. We show that scrPscrT symmetry is compatible with all known results on optical rotation in the high-temperature superconductors. We also find a o/Iunique and accessible experimental signature for the scrPscrT state.