Spatial and temporal probes in inhomogeneous systems: Theory and experiment

The experimental and theoretical challenges posed by the study of dynamically inhomogeneous systems are outlined in the context of cuprates and other oxides. Considering the pitfalls in the single-component approach to the analysis of inhomogeneous systems, the effect of either temporal or spatial averaging by different experiments is discussed. A group-theoretical symmetry analysis of the observed inhomogeneities in real space and k-space observed in the cuprates is shown to lead to a quantitatively verifiable description of the inhomogeneous state, comprising of bound singlet pairs in the ground state and unbound fermions in the excited state. The predicted symmetry breaking associated with pairing is shown to be verifiable experimentally.