Localization Catastrophe Research Articles

More on divergences in brane world models

In this paper a model in a space-time with compact extra dimension is presented, describing five-dimensional fermion fields interacting with an electromagnetic field localized on a brane. This model can be considered as a toy model for examining possible consequences of the localization of gauge fields on a brane. It is shown that in the limit of infinite extra dimension, the lowest-order amplitudes of some processes in the resulting four-dimensional effective theory are divergent. Such a ``localization catastrophe'' can be inherent to more realistic brane world models with infinite extra dimensions.

Local model for charge delocalization in partly substituted cuprate superconductors

Partial substitutions according to YBa 2(Cu 1 − xM x) 3O y with M = Ni etc. in connection with various redox sequencings allow for complex strategies in obtaining novel materials. We analyze redox related structural data on selected model compounds with special emphasis on a new local structural approach, derive aspects of their electronic behavior, and gain an expanded understanding of the charge balance function of Cu(1). We elaborate on the conditions for antitypes to conventional behavior such as n type superconductivity at low y and semi-conductivity at high y. We show that a localization catastrophe can occur when the population of (1)4 configurations (Cu(1) coordinated by 4 O) is low. In this case (1)3 and (1)2 coordinations dictate the spatial behavior of (1)4 which leads to charge localization. We show that this corresponds to a Mott type transition which has a general implication in degrading superconducting properties on further reoxygenation.