paper

Exponential Orthogonality Catastrophe at the Anderson Metal-Insulator Transition

arXiv:1606.02243 · doi:10.1103/PhysRevLett.117.146602

Abstract

We consider the orthogonality catastrophe at the Anderson Metal-Insulator transition (AMIT). The typical overlap between the ground state of a Fermi liquid and the one of the same system with an added potential impurity is found to decay at the AMIT exponentially with system size as , where is the so called Anderson integral, is the power of multifractal intensity correlations and denotes the ensemble average. Thus, strong disorder typically increases the sensitivity of a system to an additional impurity exponentially. We recover on the metallic side of the transition Anderson's result that fidelity decays with a power law with system size . This power increases as Fermi energy approaches mobility edge as where is the critical exponent of correlation length . On the insulating side of the transition is constant for system sizes exceeding localization length . While these results are obtained from the mean value of giving the typical fidelity , we find that is widely, log normally, distributed with a width diverging at the AMIT. As a consequence, the mean value of fidelity converges to one at the AMIT, in strong contrast to its typical value which converges to zero exponentially fast with system size . This counterintuitive behavior is explained as a manifestation of multifractality at the AMIT.

4 pages, 4 figures

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