%0 Journal Article %T Drift-Diffusion in Mangled Worlds Quantum Mechanics %A Robin Hanson %J Physics %D 2003 %I arXiv %R 10.1098/rspa.2005.1640 %X In Everett's many worlds interpretation, where quantum measurements are seen as decoherence events, inexact decoherence may let large worlds mangle the memories of observers in small worlds, creating a cutoff in observable world size. I solve a growth-drift-diffusion-absorption model of such a mangled worlds scenario, and show that it reproduces the Born probability rule closely, though not exactly. Thus deviations from exact decoherence can allow the Born rule to be derived in a many worlds approach via world counting, using a finite number of worlds and no new fundamental physics. %U http://arxiv.org/abs/quant-ph/0303114v2