Uniqueness of measures in loop quantum cosmology

Abstract

In Ashtekar and Campiglia [Classical Quantum Gravity 29, 242001 (2012)], residual diffeomorphisms have been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). We show that, in the homogeneous isotropic case, unitarity of the translations with respect to the extended ℝ-action (exponentiated reduced fluxes in the standard approach) singles out the Bohr measure on both the standard quantum configuration space ℝBohr as well as on the Fleischhack one (ℝ⊔ℝBohr). Thus, in both situations, the same condition singles out the standard kinematical Hilbert space of LQC.