Decoherence in Sub-Systems of an Isolated System and the Disappearance   of Quantum Multiverse
  This study was started to know mysterious classicality of nuclei.   Using three particles model without external environments, it is found that decisions of respective state of three particles by decoherence are not simultaneous. Furthermore, in this model, wave function of total three body system collapses spontaneously without any external environments. Therefore we may able to insist that a wavefunction of our universe has already collapsed spontaneously without any external observer, because of the same mechanism with this model. 
Takuji Ishikawa
quant-ph nucl-th