Background freedom leads to many-worlds with local beables and probabilities

Abstract

I argue that background freedom in quantum gravity automatically leads to a dissociation of the quantum state into states having a classical space. That is, interference is not completely well-defined for states with different space geometries, even if their linear combination is. Interference of states with different space geometry is still allowed at small scales, but precluded at macro-scales. Macrostates, including measuring devices, appear classical. The distribution of space geometries automatically gives the Born rule. The dissociation entails a kind of absolute decoherence, making the ad-hoc wavefunction collapse unnecessary. This naturally leads to a new version of the many-worlds interpretation, in which: 1) the classical space-states form an absolute preferred basis, 2) at any time, the resulting micro-branches are like classical worlds, with objects in space, 3) macro-branches stop interfering, even though micro-branches can interfere (as they should), 4) the space geometries converge at the Big-Bang, favoring macro-branching towards the future, 5) the wavefunctional becomes real by absorbing the phases in the global U(1) gauge, 6) ontologically, the wavefunctional consists of many gauged space-states, each of them counting as a world by having local beables (the space geometry and the classical fields), 7) the density of the classical space-states automatically obeys the Born rule.